Device and method for measuring workpieces

ABSTRACT

The invention relates to a device and a method for tactile/optical measuring of geometric features and structures on a workpiece. In order to be able to precisely align the probe extension for performing precise measurements without problems, a probe is proposed comprising a probe extension ( 13 ) having a flexurally elastic design at least in segments and having a mounting segment for mounting in a receptacle ( 14 ) comprising a mounting segment ( 60 ) implemented as a rotational lock.

The invention relates to a device and a method for tactile/opticalmeasuring of geometric features and structures on a workpiece. Theinvention further relates to a method for producing components of thetactile/optical sensor.

The invention relates to a probe for a tactile/optical sensor comprisinga probe extension flexurally elastic at least in segments and having amounting segment for inserting into a receptacle, the mounting segmentbeing a segment of the probe extension or a segment of the mountingelement receiving the probe extension.

Tactile/optical sensors are described in the following specifications ofthe applicant.

EP0988505 describes a method and a device wherein a probe element (firsttarget mark) and optionally a further target mark emerge from a probeextension via a flexurally elastic shaft, the coordinates thereof whendeflected being determined by means of an optical sensor.

A similar sensor is described in EP 1 071 921, wherein the contact forceis adjusted by means of the rigidity of the flexurally elastic shaft, inthat solely the bending length 1 is varied.

An opto-mechanical interface having an adjusting device for acorresponding sensor is described in EP 1 082 581.

DE 198 24 107 describes the use of a corresponding sensor for a surfaceprofiling method.

A corresponding sensor is operated on a rotating or pivoting joint in DE10 2004 022 314.

PCT/EP01/10826 describes coating a probe element or probe extension onthe side facing away from the sensor in order to generate a luminousmark in the interior of the probe element by bundling the radiationreflected at the coating, said radiation being introduced into theinterior of the shaft of the probe element or probe extension, thelength thereof being measured, and a mark associated with the probeelement and formed by a darkened region of the luminous shaft of theprobe element.

DE 10 2010 060 833 describes a tactile/optical sensor wherein, inaddition to determining the position of a contact shape element or atleast a target mark associated therewith in the X and/or Y direction ofthe coordinate measuring machine using a first sensor such as an imageprocessing sensor, a second sensor such as a distance sensor alsodetermines the Z-direction, wherein at least one flexible connectingelement is used for mounting the contact shape element and the targetmark in a mounting element, said connecting element being penetrated bythe beam path of the first sensor in the beam direction, wherein the atleast one flexible connecting element is transparent and/or is severelydefocused with respect to the first sensor. The distance sensorcapturing the deflection in the Z direction (vertical direction) of thecontact shape element or at least a target mark associated therewith isproposed to be, for example, an interferometer, particularly anabsolutely measuring heterodyne interferometer.

Full reference is made to the disclosed contents of all previously namedspecifications of the applicant.

The fundamental object of the present invention is to retain theadvantages of the prior art while simultaneously proposing a flexible,tactile/optical sensor for a plurality of different measurement tasksand a corresponding measurement method, wherein a desired alignment ofthe tactile/optical sensor shall particularly be made without trouble.The probe shall also be easily interchangeable in the receptacle orfiber receptacle thereof.

It is therefore particularly an object of the present invention torefine a probe of a tactile/optical sensor such that exact alignment canbe made without trouble.

The object is achieved substantially according to the invention by aproposed probe for a tactile/optical sensor comprising a probe extensionflexurally elastic at least in segments and having a mounting segmentfor inserting into a receptacle, the mounting segment being a segment ofthe probe extension or a segment of the mounting element receiving theprobe extension, characterized in that the mounting segment isimplemented as a rotational lock.

The invention is particularly characterized in that the mounting segmentcomprises an external geometry deviating from a circular geometry atleast in regions in a plane running perpendicular to the longitudinalaxis thereof.

The invention is further characterized in that the external geometrydeviating from a circular geometry is formed by a flat area such as aplanar segment of the mounting segment, by a protrusion protruding outof the mounting segment, by a cutout in the mounting segment, by arecess such as a groove running in the longitudinal direction of thesegment, and/or by a polygonal design of the mounting segment.

A normal can preferably be associated with the external geometrydeviating from a circular geometry, said normal running parallel or atan angle α, where α≤+/−5°, to a region of the probe extension from whicha contact shape element emerges.

According to the invention, the mounting element is preferablyimplemented as a hollow cylinder comprising an L-shaped geometry.

The invention is further characterized in that the probe extension, suchas a fiber, is inserted into the interior of a hollow cylinder, at leastin segments, wherein the hollow cylinder comprises a bend of 85° to 95°,preferably 90°, wherein preferably only non-drawn regions of the probeextension run within the hollow cylinder and preferably the probeextension and hollow cylinder are adhered to each other at the exitpoint of the probe extension out of the hollow cylinder facing towardthe contact shape element.

The receptacle or fiber receptacle preferably comprises a contactsurface for the mounting segment and adapted to the mounting segment,wherein the contact surface is preferably flat.

The invention particularly relates to a device for determining geometricfeatures and structures on a workpiece by means of a tactile/opticalsensor comprising at least a laterally measuring optical sensor,preferably an image processing sensor, preferably a vertically measuringoptical distance sensor, and an at least partially flexurally elasticprobe extension, at least the following emerging from the probeextension: a contact shape element for deflecting when contacting theworkpiece, and preferably at least one target mark associated with thecontact shape element for deflecting when the contact shape elementcontacts the workpiece, such that the lateral deflection of the contactshape element or of the target mark perpendicular to the optical axis ofthe laterally measuring optical sensor can be captured by means of thesame, and the vertical deflection of the contact shape element or of thetarget mark along the optical axis of the laterally measuring opticalsensor can be captured by means of the distance sensor.

At least some considerations of the objects are substantially achievedby a corresponding device, wherein a probe extension emerging from afiber receptacle to which a flexurally elastic part is directly orindirectly connected is used, to which part the contact shape elementand optionally the target mark is directly or indirectly connected,wherein the part of the probe extension running between the optionaltarget mark, if present, and the contact shape element is flexurallyrigid relative to the flexurally elastic part.

Here indirectly means that a flexurally rigid part is provided betweenthe fiber receptacle and the flexurally elastic part, or that aflexurally rigid part is provided between the flexurally elastic partand the contact shape element.

Two types of the tactile/optical sensor are fundamentallydifferentiated. The first is a 2D sensor, wherein the deflection of thecontact shape element or the target mark associated therewith isdetermined solely perpendicular to the optical axis of the laterallymeasuring optical sensor, preferably by means of image processing, andno vertical measurement of the deflection takes place and thecorresponding vertically measuring distance sensor is not used or is notpresent. The contact shape element is typically a spherical or nearlyspherical thickening on the end of the probe extension facing toward theworkpiece. The optional target mark can be a further thickening abovethe contact shape element and is deflected together with the contactshape element. Only the contact shape element thereby makes contact withthe workpiece.

Capturing the target mark is sensible whenever the contact shape elementis inserted deep into an opening or next to an edge of the workpiece,for example more than about 1 to 5 millimeters, depending on thediameter of the contact shape element and the optics used, because inthese cases shadowing can occur in the image of the contact shapeelement, whereby the accuracy of determining the deflection can bereduced. The target mark is preferably disposed so far above the contactshape element or inserted into the workpiece only so far that the targetmark always remains above the surface of the workpiece, that is, is notinserted and thus is not shadowed. Here inserting means moving below aworkpiece surface present directly adjacent to the contact shapeelement. Said surface itself can, for example, be present in a recess ofthe workpiece, wherein the probe extension has already been displacedwithin said recess. This does not cause a problem, however, because theedges of the recess are typically far enough away from the beam path ofthe laterally measuring sensor and thus do not shadow the same.

For the 2D sensor type, the probe extension is implemented as a fiberreceived by a fiber receptacle, that is, attached thereby, saidreceptacle in turn being mounted on the bottom side of the optic or anadjusting unit, for example by means of a magnetic changeout interface.Because the fiber receptacle should not influence the optical beam path,said receptacle is disposed laterally adjacent to the beam path. The endof the probe extension and optionally the region of the probe extensionrunning between the contact shape element and the target mark run nearlyparallel, in order to allow optimal capturing of the deflection, and asclosely as possible to the optical axis of the optic associated with thelaterally measuring optical sensor. The simplest solution for mountingin the fiber receptacle is redirecting the probe extension by about 90°,that is, providing a bend or kink point. After said redirection, theprobe extension then runs to the fiber holder (fiber receptacle)approximately 90° to the optical axis The bend point and the regionafter the bend point, and the region running into the fiber holder(fiber receptacle) should preferably be flexurally rigid in comparisonwith the flexurally elastic part of the probe extension present abovethe contact shape element or optionally above the target mark. Saidmeasure ensures that only those regions of the probe extension runningalong or parallel to the optical axis contribute to the elastic bendingof the probe extension when contacting the workpiece and the resultingdeflection, thereby resulting in a unique deflection behavior andparticularly directionally independent contact forces in the lateralmeasurement plane. The increased rigidity of said regions can beproduced, for example, in that the probe extension is enclosed by arigid sleeve, for example a metal tube or the like, that is, saidextension runs or is guided in the interior of a hollow cylinder.Alternatively, the probe extension can be implemented as a fiber havinga greater diameter in said regions in comparison with the flexurallyelastic segment.

The region between the target mark and the contact shape element ispreferably flexurally rigid or more flexurally rigid than the flexurallyelastic part, in order to transmit the deflection of the contact shapeelement during contact as fully as possible to the target mark. A highsensitivity of the deflection measurement is thereby ensured. Flexurallyrigid implementation can be ensured, for example, in that the distancebetween the contact shape element and the target mark is small incomparison with the length of the flexurally elastic part, and even haspreferably the same or approximately the same diameter. This has theadvantage that a single fiber can be used for the probe extension, onwhich the contact shape element and the target mark are mounted, forexample fused on or drawn out of the fiber. The flexurally elastic partcan also be tapered by drawing, at least in segments, on the side of thetarget mark facing away from the contact shape element, while the regionrunning between the contact shape element and the target mark is aseparately produced segment having a constant or slightly taperingdiameter, on which the contact shape element is fused, that is generatedfrom the fiber itself by means of heat input, or a separate contactshape element is adhered, preferably under the influence of heat.

According to the invention, therefore, it can be provided that the probeextension comprises a flexurally rigid part, relative to the flexurallyelastic part, at least in the region of the fiber receptacle, preferablyin that the diameter of the probe extension is greater in comparisonwith the flexurally elastic part, or in that the probe extension runsthrough the interior of a hollow cylinder.

According to an embodiment of the invention, the probe extension runs atan angle of approximately 90°, particularly at an angle from 88° to 92°to the optical axis of the laterally measuring optical sensor in theregion of the fiber receptacle, and the region having the contact shapeelement comprises a segment having a bend, wherein the segment ispreferably flexurally rigid in design in comparison with the flexurallyelastic part.

The second type provides a 3D sensor, wherein in addition to the lateralmeasurement of the deflection, the vertical deflection is alsodetermined by means of a distance sensor. Embodiments of this type areknown, wherein the vertical deflection of the contact shape elementitself is determined, such as is described by DE 10 2014 111 086.2,still unpublished at the time this application is submitted. The targetmark described with respect to the 2D sensor type can also be capturedby mans of the distance sensor when implemented correspondingly. Aseparate target mark is preferably used for the vertical deflectionmeasurement, however, particularly preferably on the top side of theprobe extension, as the side of the probe extension facing away from theworkpiece and facing toward the optic. Said target mark can be the upperend of a fiber, for example, serving as a base body for the probeextension. Said upper end can be polished or coated or provided with amirrored or partially mirrored plate in order to function as a reflectorfor the measurement beam of the distance sensor. The distance sensoruses the same front objective as the image processing sensor, thereforeat least partially comprises a common beam path with the same. This isnecessary in order to keep the size of the entire arrangement small andin order for the lateral and vertical deflection to be present indefined directions relative to each other.

Typical distance sensors are Foucault distance sensors, focus sensors,interferometric distance sensors, or chromatic or chromatic confocaldistance sensors. The beam path of the distance sensor can run partiallythrough the optic used for the laterally measuring sensor, particularlyin the region facing toward the workpiece, that is, using the same frontoptic, or the distance sensor can have a dedicated beam path. The formercan be implemented for Foucault distance sensors, focus sensors, andparticularly chromatic confocal distance sensors, for example, such asis described in EP1299691 for Foucault distance sensors or inWO2009049834A2 for chromatic confocal distance sensors.

The distance sensor can also be a photogrammetric distance sensor.

For the 3D sensor type, contact forces in all three spatial directionsshould be independent of the direction, but at least the contact forcein the vertical direction should be similar in comparison with that inthe lateral directions. A flexural elasticity must therefore also bepresent in the vertical direction. This is preferably implemented inthat the probe extension is mounted on a spring element such as a leafspring or leaf spring arrangement extending perpendicular to the opticalaxis and dimensioned as appropriately thin in the direction of theoptical axis and having a correspondingly low rigidity in the verticaldirection. Said leaf spring arrangement thus serves as the fiberreceptacle and comprises a corresponding chucking point for the probeextension. In order that the spring elements influence the opticalimaging of the image processing sensor as little as possible, saidelements are disposed outside of the focal plane of the beam path of theimage processing sensor, thus above the contact shape element oroptionally the target mark, and implemented alternatively oradditionally transparent to the image processing sensor. Said elementsthus appear out of focus in the image of the laterally measuring opticalsensor, thus for example of the image processing sensor, and thus inpractice merely limit the amount of light available for the analysis.The separate target mark for the distance sensor is mounted above thechucking point on the probe extension, whereby the measurement beam ofthe distance sensor is not influenced by the spring elements. Theseparate target mark is thereby also imaged only severely out of focuswith respect to the image processing sensor. The spring elements emergefrom a retaining element present outside of the beam path. Said elementcan have a stable ring structure, for example, attached to the bottomside of the optic or of an adjusting unit, for example by means of amagnetic changeout interface.

According to the invention, therefore, the fiber receptacle comprises atleast one flexurally elastic element such as a leaf spring or leafspring arrangement, wherein the flexurally elastic element

-   -   emerges from a retaining element preferably disposed outside of        the beam path of the laterally measuring optical sensor, and    -   runs nearly perpendicular to the optical axis of the laterally        measuring optical sensor, and    -   comprises a clamping point for receiving the probe extension,        and    -   is preferably transparent and/or disposed out of focus relative        to the beam path of the laterally measuring optical sensor.

The following embodiments apply equally to the 2D sensor and 3D sensortypes.

Corresponding adjustment mechanisms are provided for adjusting the probeextension relative to the optical axis in both the translational and therotational degrees of freedom. Said mechanisms can be manual ormotorized means. The goal of the adjusting is to align the contact shapeelement or, if captured by the laterally measuring optical sensor, thetarget mark into the focal plane of the optic of the image processingsensor and along the optical axis, and setting the direction of theprobe extension in the lower region facing toward the workpiece in adefined manner. Said direction is preferably set to an angle of 0°, thatis, parallel to the optical axis, or a slight angle, for example0°<Alpha<15°, preferably 0°<Alpha<5°, particularly preferably0°<Alpha<1°. Standard measurements take place at 0° angle, while slightangles are particularly well suited for measurements wherein the probeextension is inserted into the workpiece a great distance along a wallor edge or where for other reasons shaft contact, that is, contactbetween the workpiece and the region of the probe extension above thecontact shape element or the target mark, and therefore a falsedeflection can occur. A small angle of a few degrees can also be usedfor measuring the roughness of a workpiece surface. Depending on thelocation and orientation of the surface to be measured, particularly forvertically oriented surfaces on the workpiece, the direction of theangle must be set. To this end, various solutions according to theinvention are available.

According to a first solution, the angle for the corresponding directionis set by means of adjusting means. This is very inconvenient whenmeasuring surfaces of different orientations, however, as a newadjustment is needed every time. If different probe extensions are alsoplanned in one measurement sequence, then the adjusting means may needto be set separately for each probe extension.

It can therefore also be provided that a changeout interface formounting various probe extensions is provided on the adjusting means.Said changeout interface is implemented for changing out the fiberreceptacle including the probe extension mounted therein. The changeoutpreferably takes place automatically and corresponding fiber receptaclesare stored in a changeout magazine, for example. The changeout interfaceis preferably a magnetic interface. It is thereby possible, in the formof a second solution, to automatically change in probe extensionsalready having the corresponding angle without requiring anotheradjustment. To this end, the bend of the probe extension in the 2Dsensor type already has a corresponding angle in the correspondingdirection, or the clamping in the clamping point for the 3D sensor typeis implemented correspondingly, that is, the probe extension is clampedat a corresponding angle. By means of the changeout interface, probeextensions having different lengths or equipped with contact shapeelements of different thicknesses can be used automatically in ameasurement sequence, thus providing very high flexibility.

According to a third solution, a changeout interface is provided formounting the adjusting means and the fiber receptacle mounted thereon,or for mounting the fiber receptacle itself, if no adjusting means areused, or for mounting the mounting element used for the 3D sensor typeson the laterally measuring optical sensor or a mount associatedtherewith, providing mounting at various angle positions about theoptical axis. It is thereby possible to use to the same fiber in oneautomatic measurement sequence for differently oriented surfaces withoutany adjustment being necessary. The adjusting means can either beeliminated or must be set only once. The angle positions for mountingcan be implemented in an arbitrary number of steps, but preferably fourpositions offset or rotated 90° from each other are preferablysufficient. For the case according to the invention that the lightsource for illuminating the contact shape element or the target mark isintegrated in the fiber holder (fiber receptacle) for the embodiment asa 2D sensor and must be changed out or rotated along with the same, towhich end corresponding electrical contacts for actuation must bepresent in the changeout interface, as few rotational positions aspossible should be provided.

According to a particularly preferred solution, therefore, means areprovided for adjusting the probe extension, particularly together withthe fiber receptacle, relative to the laterally measuring optical sensorand comprise at least one manually driven or motorized translational orrotational adjusting mechanism, preferably that means are provided foradjusting at least two translational and at least two rotational degreesof freedom.

It is also preferable that the means for adjusting comprise a changeoutinterface, preferably a magnetic interface, for mounting interchangeablefiber receptacles.

In a further preferred embodiment of the invention, the region of theprobe extension comprising the contact shape element is at an angle of0°<α<15° relative to the optical axis of the laterally measuring opticalsensor, in that

-   -   the bend of the probe extension is implemented between the        region of the fiber receptacle and the region comprising the        contact shape element, or    -   the clamping point is implemented accordingly, or    -   the means for adjusting can be set accordingly.

The idea is particularly emphasized that the means for adjustingcomprise one, preferably additional changeout interfaces, preferablymagnetic interfaces, for mounting on the laterally measuring opticalsensor or a mount associated therewith, wherein the means for adjustingcan be mounted in a plurality of positions, preferably four spaced 90°apart, rotationally offset about the optical axis of the laterallymeasuring optical sensor.

According to an alternative proposal, the mounting element comprises achangeout interface, preferably magnetic interface, for mounting on thelaterally measuring optical sensor or a mount associated therewith,wherein the mounting element can be mounted in a plurality of positions,preferably four spaced 90° apart, rotationally offset about the opticalaxis of the laterally measuring optical sensor.

As further refinement of said idea, a device is provided wherein a lightsource such as an LED, SLED, laser diode, or the like is fixedlyconnected to the interchangeable fiber receptacle and the changeoutinterface for mounting the fiber receptacle comprises contacts fortransmitting signals for actuating the light source.

Tactile/optical sensors according to the prior art are mounted on arotary/tilting joint for measuring undercuts, particularly undercuts atany arbitrary orientation. This has the disadvantage that the accuracyof the measure is reduced due to inaccuracies in the rotary/tiltingjoint. In order to avoid said disadvantage, according to the invention,probe extensions protruding laterally or star-shaped or generallybranching in a plurality of directions are provided, wherein a contactshape element is provided on each branch. The branching preferably takesplace below a target mark, so that the same target mark can be used fordetermining the deflection of all contact shape elements.

It can therefore be provided according to the invention that the probeextension runs in a modified direction between the target mark and thecontact shape element or comprises a preferably star-shaped branching toa plurality of contact shape elements.

In order to implement sensitive measuring by means of such laterallyprotruding contact shape elements, design measures must be taken suchthat the deflection of the contact shape element is transferred to atarget mark or the target mark to a large degree, and does not lead tosignificant bending of the protruding region, that is, the region havinga modified direction, or torsion of the probe extension, that is,rotation about the optical axis of the laterally measuring sensor, alongwhich the part running about the target mark runs at least in part. Tothis end, it must be considered that the torque is transmitted to thetarget mark by means of the lever arm formed by the region of modifieddirection or branching as a function of the flexural rigidity thereof,thereby giving rise to the torsion of the probe extension. The greaterthe torsion, the less the proportion of deflection of the contact shapeelement transferred to the target mark for measuring, whereby thesensitivity is reduced and measurement accuracy decreases. In order tocounteract said effect, the ratio between the distance between thecontact shape element and the target mark perpendicular to the opticalaxis, that is, the length of the lever arm, and the flexural rigidity ofthe region of the modified direction and torsional rigidity of theregion of the probe extension above the target mark is dimensioned assmall as possible. The protruding region must therefore be implementedas rigid in itself, particularly flexurally rigid transverse to thepotential contact forces. The least flexural rigidity occursperpendicular to the protrusion, based on the type, thus in thedirection running perpendicular to the modified direction andperpendicular to the optical axis, that is, perpendicular to the regionin which the probe extension runs above the target mark. The protrudingregion can be implemented rigidly enough only in that said region isvery short in design, such as only approximately 1 to 4 mm long. Typicaldiameters for the fiber present in the protruding region—as well as forthe fiber present in the flexurally elastic part above the targetmark—are generally in the range from 10 μm to approximately 300 μm. Fromsaid range, suitable ratios must then be found, so that a largeproportion of the deflection is transferred to the target mark. To thisend, the region of the probe extension running along the optical axisabove the target mark must be implemented long enough to be flexurallyelastic, but also short enough to remain torsionally rigid. As anexample, for a fiber thickness of approximately 100 μm to 200 μm,preferably approximately 130 μm, and a typically glass material for thefiber, for a 1 mm to 2 mm, preferably 1.2 mm long protrusion, saidrequirement results in a fiber length above the target mark to the fibermount of about 7 mm to 13 mm, preferably 10 mm. In a preferredembodiment, the transfer ratio between the deflection of the contactshape element and the deflection of the target, each in the directionperpendicular to the protrusion and to the optical axis, isapproximately 1:0.83. Typical diameters for the contact shape elementand the target mark are 200 μm to 300 μm, preferably 250 μm. Theremaining deviation between the deflection of the contact shape elementand the deflection of the target mark is corrected by calibrating saidbehavior, in that, for example, a so-called directionally dependentcharacteristic deflection curve is created.

In a further preferred embodiment of the invention, the torsionalrigidity of the probe extension about the axis running along the opticalaxis of the image processing sensor is selected, by selecting thediameter and length thereof in the regions above the target mark andbetween the target mark and the contact shape element, to be greatenough that the deflection of the contact shape element in the directionrunning perpendicular to the optical axis and perpendicular to themodified direction is transferred at least 50%, preferably at least 70%,particularly preferably at least 80% to the target mark.

The optic associated with the laterally measuring optical sensor andoptionally also with the vertically measuring sensor is refined in orderto increase the accuracy and/or flexibility thereof. For the lateraldeflection measurement, a precise measurement requires that the imagingscale remains constant within vertical positions of the contact shapeelement or the target element resulting from the vertical deflectionsthat occur. Otherwise the lateral deflection would be determined havinga lateral offset depending on the vertical deflection, and thereforefalsely. To this end, the optic is telecentric in design, for example inthat a telecentric optic having a fixed imaging scale or a telecentriczoom stage of a zoom optic is used. Additionally or alternatively, itshould be possible to set the accuracy for the lateral and/or verticalmeasurement or to adjust the imaging scale to the size of the contactshape element or target mark selected in each case, so that saidelements can still be completely captured considering the maximumpermissible lateral deflection and the measurement can take place at themaximum possible resolution and therefore accuracy. Said object isachieved according to the invention by using a zoom optic, wherein thevarious zoom stages should be available for the working distancerequired in each case due to different lengths of the probe extensions,in that preferably a zoom optic having a working distance adjustableindependently of the imaging scale is used. If a zoom optic is also usedfor the distance sensor (for the 3D sensor type), then either a largemeasurement range or a high accuracy is possible for determining thevertical deflection.

It can therefore also be characteristic that a telecentric optic havinga fixed imaging scale and/or a zoom optic having an adjustable workingdistance preferably independent of the imaging scale is used for thelaterally measuring optical sensor and/or the vertically measuringoptical distance sensor, wherein the zoom optic preferably comprises atleast more than one zoom stage bringing about a telecentric image.

The idea is particularly emphasized that the laterally measuring sensorand the vertically measuring distance sensor at least partially have acommon beam path, particularly in the region of the optic facing theworkpiece, wherein the distance sensor is preferably a distance sensorusing the Foucault principle or a focus sensor or a chromatic confocalsensor.

In order to increase the measurement range of the vertically measuringsensor, said sensor can be implemented as a Foucault distance sensor ina refined variant of the invention. According to the prior art, in aFoucault distance sensor the measurement beam is imaged in the directionof the workpiece after the Foucault knife-edge fills half the apertureof the optic. When the surface captured by the measurement beam istilted and/or deflected, the reflected measurement beam is thereforepartially shadowed by the optic, whereby the analyzed measurement beamis deformed and the analysis becomes less accurate, or the permissiblerange of deflection or tilting is limited. This is improved according tothe invention in that the light source for the measurement beam is alighting source filling only a limited region of the aperture of theoptic, such as a severely collimated punctiform light source. A furtherincrease in the measurement range is implemented according to theinvention in that, in place of the differential diode arrangementstypical in the prior art, a position-sensitive diode (PSD—positionsensitive device) or a CCD or CMOS camera is used as the received andcan detect a greater lateral deflection of the reflected measurementbeam. Planar cameras or planar PSD can be used, as well as linearcameras or linear PSDs. In order to increase the scanning frequency forplanar cameras, only an adjustably limited region, particularly alimited number of lines (line limitation), is read. The lines arethereby spaced apart from each other perpendicular to the direction ofthe deflection to be measured. The complete deflection can thereby takeplace even with line limitation. A gap limitation is advantageous,particularly for CMOS sensors, and is used if the expected deflectionsdo not reach the edge of the camera chip.

The proposal is particularly emphasized that the vertically measuringoptical distance sensor is a sensor using the Foucault principle,wherein a lighting source illuminates only a limited part of theaperture of the optic used for imaging on the workpiece, and/or whereina linear or planar detection unit such as a position-sensitive diode(PSD) or camera is used for determining the location of the lightingreflected by the workpiece.

The invention further relates to a device, wherein the tactile/opticalsensor is integrated in a coordinate measuring machine, preferably amultisensor coordinate measuring machine, together with other sensors,preferably tactile, optical, or computed-tomography sensors, preferablysuch that the laterally measuring optical sensor and the verticallymeasuring optical distance sensor can be operated independently of thetactile/optical sensor.

This means, for example, that the laterally measuring optical sensor andthe vertically measuring optical distance sensor can be usedalternatively for measuring the workpiece surface when the probeextension is set aside, that is, when the fiber receptacle, adjustingunit, or mount are set aside.

The invention further relates to a device for determining geometricfeatures and structures on a workpiece by means of a tactile/opticalsensor comprising at least a laterally measuring optical sensor,preferably an image processing sensor, preferably a vertically measuringoptical distance sensor, and an at least partially flexurally elasticprobe extension, at least the following emerging from the probeextension: a contact shape element for deflecting when contacting theworkpiece, and preferably at least one target mark associated with thecontact shape element for deflecting when the contact shape elementcontacts the workpiece such that the lateral deflection of the contactshape element or the target mark perpendicular to the optical axis of alaterally measuring optical sensor can be captured by means of theoptical sensor, and preferably the vertical deflection of the contactshape element or of the target mark along or nearly along the opticalaxis of the laterally measuring optical sensor being able to be capturedby means of the distance sensor, characterized in that the probeextension emerges from a fiber receptacle to which a flexurally elasticpart is directly or indirectly connected is used, to which part thecontact shape element or optionally the target mark is directly orindirectly connected, wherein the part of the probe extension runningbetween the optional target mark, if present, and the contact shapeelement is flexurally rigid relative to the flexurally elastic part, andthat means for adjusting the probe extension comprise a changeoutinterface for mounting interchangeable fiber receptacles.

The invention particularly relates to a device for determining geometricfeatures and structures on a workpiece by means of a tactile/opticalsensor comprising at least a laterally measuring optical sensor,preferably an image processing sensor, preferably a vertically measuringoptical distance sensor, and an at least partially flexurally elasticprobe extension, at least the following emerging from the probeextension: a contact shape element for deflecting when contacting theworkpiece, and preferably at least one target mark associated with thecontact shape element for deflecting when the contact shape elementcontacts the workpiece such that the lateral deflection of the contactshape element or the target mark perpendicular to the optical axis of alaterally measuring optical sensor can be captured by means of theoptical sensor, and preferably the vertical deflection of the contactshape element or of the target mark along or nearly along the opticalaxis of the laterally measuring optical sensor being able to be capturedby means of the distance sensor, characterized in that the probeextension emerges from a fiber receptacle to which a flexurally elasticpart is directly or indirectly connected, to which part the contactshape element or optionally the target mark is directly or indirectlyconnected, wherein the part of the probe extension running between theoptional target mark, if present, and the contact shape element isflexurally rigid relative to the flexurally elastic part, and that meansare provided for adjusting the probe extension, particularly togetherwith the fiber receptacle, relative to the laterally measuring opticalsensor and comprise at least one manually operated or motorizedtranslational or rotational adjusting mechanism, preferably that meansfor adjusting at least two translational and at least two rotationaldegrees of freedom are provided, that the means for adjusting comprise achangeout interface, preferably a magnetic interface, for mountinginterchangeable fiber receptacles, and/or that the means for adjustingcomprise one, preferably additional, changeout interface, preferably amagnetic interface, for mount on the laterally measuring optical sensoror a mount associated therewith, wherein the means for adjusting prefercan be mounted at a plurality of rotationally offset positions,preferably four spaced at 90°, about the optical axis of the laterallymeasuring optical sensor.

The invention further relates to a device for determining geometricfeatures and structures on a workpiece by means of a tactile/opticalsensor comprising at least a laterally measuring optical sensor,preferably an image processing sensor, preferably a vertically measuringoptical distance sensor, and an at least partially flexurally elasticprobe extension, at least the following emerging from the probeextension: a contact shape element for deflecting when contacting theworkpiece, and preferably at least one target mark associated with thecontact shape element for deflecting when the contact shape element (8)contacts the workpiece, such that the lateral deflection of the contactshape element or of the target mark perpendicular to the optical axis ofthe laterally measuring optical sensor can be captured by means of thesame, and the vertical deflection of the contact shape element or of thetarget mark along the optical axis of the laterally measuring opticalsensor can preferably be captured by means of the distance sensor,characterized in that the probe extension emerges from a fiberreceptacle to which a flexurally elastic part is directly or indirectlyconnected, to which part the contact shape element or optionally thetarget mark is directly or indirectly connected, wherein the part of theprobe extension running between the optional target mark, if present,and the contact shape element is flexurally rigid relative to theflexurally elastic part, and that the vertically measuring opticaldistance sensor is a sensor using the Foucault principle, wherein alighting source illuminates only a limited part of the aperture of theoptic used on the workpiece, and/or wherein a planar detection unit suchas a position-sensitive diode (PSD) or camera is used for determiningthe location of the lighting reflected by the workpiece.

The invention further relates to a method for determining geometricfeatures and structures on a workpiece using a probe of atactile/optical sensor comprising a probe extension flexurally elasticat least in segments and having a mounting segment for inserting into areceptacle or fiber receptacle, the mounting segment being a segment ofthe probe extension or a segment of the mounting element receiving theprobe extension, and characterized in that the mounting segment isimplemented as a rotational lock.

In particular, according to the invention, the mounting segment has anexternal geometry deviating at least in segments from a circulargeometry in the region thereof running in the receptacle in a planerunning perpendicular to the longitudinal axis of the mounting segment,to which geometry the internal geometry of the receptacle is adapted.

The invention is further characterized in that the external geometrydeviating from the circular geometry is formed by a flat area such as aplanar segment of the mounting segment, by a protrusion protruding outof the mounting segment, by a cutout running in the mounting segment, bya recess such as a groove running in the longitudinal direction of thesegment, and/or by a polygonal design of the mounting segment.

In particular, according to the idea having independent protection, theprobe extension is implemented so that the probe extension comprises apartially planar flat area at least in the region of the fiberreceptacle, preferably that the flat area is formed by an at leastpartially flattened external side of the hollow cylinder in whichregions of the probe extension are inserted.

The object disassociated from the rest of the invention can thereby beachieved, that the probe extension is disposed at a defined location inthe fiber receptacle. The advantage thereby arises that the direction ofthe region of the probe extension running parallel to or along theoptical axis and comprising the contact shape element and optionally thetarget mark, is precisely determined, even if the probe extension isreplaced with the same type of probe extension, for example due to wear.

The implementation of the flat area is preferably used for the “2Dsensor” type. The flat area is particularly preferably formed on theregion of the hollow cylinder inserted into the fiber receptacle, intowhich the probe extension is inserted, after the hollow cylinder hasbeen bent by 90°. The fiber receptacle also comprises such a contactsurface as a mating part. Alternative embodiments, wherein the probeextension or the hollow cylinder are cylindrical and the contact surfaceis implemented in the form of a V-groove, for example, have thedisadvantage that the probe extension can be disposed at differentrotational orientations in the V-groove.

In a particular embodiment of the invention, the fiber receptaclecomprises a contact surface for the flattened region of the probeextension or the hollow cylinder, wherein the contact surface ispreferably flat.

The normal direction of the flat area is preferably parallel to thedirection of the region of the probe extension running parallel to oralong the optical axis, and the hollow cylinder preferably has a bend of90°.

The bending of the hollow cylinder or the probe extension is thusperformed such that the bent part runs along the desired direction ofthe probe extension in the region of the contact shape element or targetmark. This is achieved, for example, in that the flattened region isplaced in a bending device on a contact surface having a definedorientation to the bending direction. The orientation of the flat areato the bend is thus set with reproducible accuracy.

An alternative embodiment of the bend of the hollow cylinder for specialmeasurement tasks also provides for the bend to be made in the rangefrom 85° to 95°.

The probe extension is particularly preferably adhered to the hollowcylinder at the exit thereof out of the hollow cylinder facing towardthe contact shape element, in order to fix the probe extension in thehollow cylinder.

According to the invention, the probe extension runs within the interiorof a hollow cylinder, at least in segments, wherein the hollow cylindercomprises a bend of 85° to 95°, preferably 90°, wherein preferably onlynon-drawn regions of the probe extension run within the hollow cylinderand preferably the probe extension and hollow cylinder are adhered toeach other at the exit point of the probe extension out of the hollowcylinder facing toward the contact shape element.

A further advantage of the flat area is that the contact of the probeextension in the fiber receptacle defined thereby ensures that lightsource aligned toward the end of the probe extension facing away fromthe contact shape element and mounted in the fiber receptacle can couplelight into the probe extension at a high coupling efficiency, even ifthe probe extension is changed out.

A flat area is synonymous with a geometric design bringing about arotational lock.

The invention further relates to a method for determining geometricfeatures and structures on a workpiece by means of a tactile/opticalsensor comprising at least a laterally measuring optical sensor,preferably an image processing sensor, preferably a vertically measuringoptical distance sensor, and an at least partially flexurally elasticprobe extension, at least the following emerging from the probeextension: a contact shape element deflecting when contacting theworkpiece, and preferably at least one target mark associated with thecontact shape element and deflecting when the contact shape elementcontacts the workpiece, the lateral deflection of the contact shapeelement or of the target mark perpendicular to the optical axis of thelaterally measuring optical sensor being captured by means of the same,and the vertical deflection of the contact shape element or of thetarget mark along the optical axis of the laterally measuring opticalsensor being captured by means of the distance sensor.

At least some considerations of the objects are substantially achievedby a corresponding method, wherein a probe extension emerging from afiber receptacle to which a flexurally elastic part is directly orindirectly connected is used, to which part the contact shape element oroptionally the target mark is directly or indirectly connected, whereinthe part of the probe extension running between the optional targetmark, if present, and the contact shape element is flexurally rigidrelative to the flexurally elastic part.

In order to be able to measure as flexibly as possible using adjustablepoint density, measurement speed, and accuracy, the invention proposesswitching between single point measurements and various scanningmethods. Different, correspondingly suitable probe extensions may beused for the different methods and are preferably automatically changedout.

In a first selectable operating mode for particularly high accuracies,the measurement points are recorded individually. To this end, thecontact shape element is displaced toward the workpiece and deflected upto a predefined magnitude. The position of the sensor relative to theworkpiece and the deflection are then determined and the measurementpoint is calculated and the contact is broken off. Alternatively, theposition of the sensor and the deflection can be determined multipletimes and/or even during the contacting process and a measurement pointcan be determined by averaging a plurality of value pairs.

According to a particularly preferred solution, according to theinvention, a probe extension is changed in manually or automatically bymeans of which measurement points on the workpiece can each bedetermined in single-point mode, in that the following steps areperformed:

-   -   the contact shape element and workpiece are displaced toward        each other relative to each other until a predefined deflection        of the contact shape element or the target mark has been        achieved    -   the contact shape element and workpiece are displaced relative        to each other away from each other at least until the contact        shape element or the target mark is no longer deflected    -   the deflection of the contact shape element and/or the target        mark is determined during the displacement toward each other        and/or during the displacement away from each other and/or        between the two displacements,    -   one measurement point each is calculated from the one or more        determined deflections and the location of the tactile/optical        sensor relative to the workpiece in each case, preferably using        the positions of the measurement axes of a coordinate measuring        machine.

In a second selectable operating mode for particularly rapid recordingof many measurement points on a track or in a region of the workpiecesurface, various scanning methods are provided. General features ofscanning are that after displacing toward the workpiece and deflectingthe contact shape element to a specified value, a plurality ofmeasurement points are recorded cyclically, wherein the contact shapeelement and the workpiece travel along a path relative to each other andremain in contact. Only after all planned measurement points have beenrecorded, that is, after the path has been travelled, is the contactbroken off.

According to a particularly preferable alternative solution, accordingto the invention, a probe extension is changed in manually orautomatically by means of which a plurality of measurement points,preferably offset from each other, on the workpiece can each bedetermined in scanning mode, in that the following steps are performed:

-   -   the contact shape element and workpiece are displaced toward        each other relative to each other until a predefined deflection        of the contact shape element or the target mark has been        achieved    -   the contact shape element and workpiece are displaced relative        to each other along a path, wherein the contact shape element        and the workpiece remain in contact, and wherein the deflection        of the contact shape element and/or the target mark is        determined cyclically during the displacement    -   the contact shape element and workpiece are displaced relative        to each other away from each other at least until the contact        shape element or the target mark is no longer deflected    -   the plurality of measurement points are calculated from the        plurality of determined deflections and the location of the        tactile/optical sensor relative to the workpiece in each case,        preferably using the positions of the measurement axes of a        coordinate measuring machine.

A plurality of methods are provided for defining the path along whichthe measurement points are recorded when scanning Methods wherein thedeflection is controlled (controlled scanning) between a minimum andmaximum value about a target value (target deflection) aredifferentiated from methods wherein no regulation takes place(uncontrolled scanning). Also differentiated are scanning on a specifiedpath and scanning without a specification of the path. In the secondcase, the path is determined at least by defining a starting point andan ending point, wherein said method is usable in practice only forcontrolled scanning (with the exception of a workpiece surface havingmaximum deviations no greater than the permissible deflections along thedirect line connecting the starting and ending points.)

When scanning along a specified path (target path), the relative motionbetween the sensor and workpiece on said target path is recorded, and inthe uncontrolled case the deflections are recorded. Said uncontrolledscanning is used whenever the workpiece surface is known preciselyenough in the context of the permissible deflections. Otherwise thepermissible deflection would be exceeded. The deflection is monitored tothis end and scanning is interrupted if necessary. The target path canthereby be arbitrarily located in space and all necessary axes of motionof the coordinate measuring machine are used for the relative motionbetween the workpiece and the tactile/optical sensor.

Alternatively, scanning takes place along a specified track ascontrolled scanning. The attempt is made to follow the target path andsimultaneously regulate the specified deflection. This is preferablysuccessful according to the invention if the target path is followed inthe two coordinate directions defined by a so-called scanning plane andthe deflection is controlled in the coordinate direction perpendicularthereto. The three coordinate directions are preferably parallel to theaxis drives of the coordinate measuring machine used for executing therelative motion. Only one axis drive is thereby used for regulating thedeflection and the other two axis drives are used for the motion on thetarget path. It is also provided, however, that regulating can occur inall three spatial directions, that is, that all axis drives are used forregulating. Because the motion along the path must be fundamentallytangential to the workpiece surface being contacted in each case, thatis, perpendicular to the deflection in each case, in order to avoidlosing contact with the workpiece surface, the regulating occursperpendicular to the surface tangent, that is, in the direction of thedeflection.

The target path is a spline, for example, defined by contours taken froma CAD model of the workpiece or previously measured contours on theworkpiece, or basic geometric shapes such as the line, line segment,circle, segment of a circle, or segment of a helix.

It is therefore preferably provided that a target path such as a splineis defined for the path and is formed by one or more specified curves inspace, wherein the curves are defined preferably based on previouslymeasured points and/or a model such as a CAD model of the workpieceand/or from basic geometric shapes such as the line, line segment,circle, segment of a circle, or segment of a helix, and the path eithercorresponds to the target path (uncontrolled scanning) or follows thetarget path providing for the deflection of the contact shape elementand/or the target mark, preferably in at least two coordinate directionsdefined by a scanning plane (controlled scanning).

When scanning without a specified target path, the path is defined inthat at least one starting and one ending point are defined, betweenwhich the path is to run. It is further preferably provided thatintermediate points through which the path runs are defined. The path tobe traveled between the starting and ending points or the intermediatepoints is derived using the workpiece surface by controlling thedeflection. In the general case, the control takes place in all threespatial direction, thus using all three axis drives. In order to avoidlosing contact with the workpiece surface, the regulating occursperpendicular to the surface tangent, that is, in the direction of thedeflection, and the motion along the path is fundamentally tangential tothe workpiece surface being contacted, that is, perpendicular to thedeflection in each case, and in the direction of the path, that is,toward the ending point or the next intermediate point.

According to a particularly preferred solution, scanning without aspecified path is successful if the path running between the startingand ending points is limited by specifying a scanning plane. This meansthat the path runs within said scanning plane. The deflection ispreferably also controlled in the two spatial directions defining thescanning plane. In order to define the exact direction of the controlledmotion and the direction of motion on the path, the direction of thedeflection, preferably the direction of the deflection projected intothe scanning plane, is first determined. Said direction is approximatelyperpendicular to the workpiece surface currently being contacted. Thecontrol therefore takes place subsequently in the direction ofdeflection, or of the deflection projected into the scanning plane, andthe motion is perpendicular thereto, that is, along the correspondingsurface tangent. The sense of direction of the motion is defined so thatno motion in the opposite direction is suddenly introduced, that is, sothat the smaller angle to the previous direction of motion is used.

In order to specify which direction the path should take when beginningfrom the starting point, it is preferably provided that a direction isspecified, for example by indicating a directional point. The scanningmotion then begins, as seen from the starting point, in the directdirection or in direction projected into the scanning plane toward thedirectional point. The definition of the scanning place can be madeusing the starting point or ending point in conjunction with a vectorforming the normal vector to the scanning plane, for example.Alternatively, a plane defined by two coordinate measuring machine axesand shifted to the starting point or the ending point can also be usedas the scanning plane.

It can also be characteristic, therefore, that the path is defined by astarting point and an ending point, and preferably by one or moreintermediate points, and preferably by a starting direction and/or ascanning plane, and that between the defined points the path isdetermined by providing for the deflection of the contact shape elementand/or target mark (controlled scanning) by the location of theworkpiece surface being contacted.

The idea is particularly emphasized that the deflection during thedisplacement on the path is controlled between a minimum and a maximumvalue about a target deflection by displacing corresponding coordinatemeasuring machine axes, wherein the control preferably takes placeperpendicular to a scanning plane or in the two spatial directionswithin the scanning plane or in all three spatial directions.

It is preferably provided, when controlling in the two spatialdirections within the scanning plane, that the control takes place inthe direction of the deflection, preferably in the direction of thedeflection projected into the scanning plane, and the displacement alongthe path within the scanning plane takes place perpendicular to thedeflection projected into the scanning plane, wherein the sense ofdirection of the displacement is defined so as to form the smaller angleto the previous direction of displacement.

Special forms of scanning also exist, such as scanning while using arotary axis. The rotation of the workpiece can thereby be understood asa further axis of motion of the coordinate measuring machine used forthe relative motion between the tactile/optical sensor and theworkpiece. The path can thereby be specified in the same way, thuscomprises as a further coordinate an angle of rotation at each point onthe path, or scanning is done without a specified path. Controlled anduncontrolled scanning are also possible. The considerations according tothe invention about the scanning plane and the directions for controland motion can be applied to the use of the rotary axis. Rotary axisscanning is preferably used for rotationally symmetrical components suchas shafts or tools, but also for crankshafts or the like. Contactthereby takes place perpendicular to the direction of the axis ofrotation on the external circumference of the workpiece, that is, in aplane in which the axis of rotation also lies. The contact and controlof the deflection preferably takes place in the lateral direction forthe 2D sensor type, that is, perpendicular to the optical axis, andperpendicular to or along the optical axis for the 3D sensor type. Thelinear axis of motion perpendicular to the contact direction and axis ofrotation is typically not used for rotary axis scanning, while insteadthe rotary axis is rotated in order to implement the motion along theworkpiece surface.

In order to perform scanning, but also measurement of single points,using the tactile/optical sensor in a manner analogous to measurementusing conventional tactile sensors, that is, as if using classicaldistance measurement systems, thereby reducing the effort for thecorresponding method, according to the invention, the three Cartesiandeflection signals are optionally derived from the images recorded bymeans of the laterally measuring optical sensor and the verticallymeasuring distance sensor, as with a conventional tactile sensor. Saidsignals can then be processed by an identical or even the same analysisunit or analysis software. For the greatest accuracy, the recording ofthe signals must be synchronized with determining the positions of themeasurement axes of the coordinate measuring machine, such as bytriggering via a trigger line.

According to a particular embodiment of the invention, probe extensionsare used for scanning having greater flexural rigidity in comparisonwith single point measurement, so-called scanning fibers. This isachieved in that the region of the probe extension running directlyabove the contact shape element or the target mark transitions after aso-called free shaft length of about 0.5 mm to 1 mm into a thickerregion of significantly greater flexural rigidity in comparison with thefree shaft length. The transition from the thicker into the thinnerregion is preferably continuous, produced by means of a drawing process.For probe extensions for single point measurements, the free shaftlength is greater, approximately 3 mm to 6 mm. For scanning fibers, alesser depth of insertion into the workpiece is possible, namely onlythe range of the free shaft length, but a so-called shaft contact willoccur only for larger deflections, as when measuring single points,wherein the part of the probe extension running above the contact shapeelement collides with the workpiece. The greater permissible deflectionswhen using scanning fibers makes controlling the deflection whilescanning easier, and allows greater scanning speeds.

Therefore, according to the invention, the probe extension transitionsfrom a flexurally elastic region adjacent to and directly above thecontact shape element or target mark into a region having a greaterdiameter, preferably at least double the diameter of the least diameterof the flexurally elastic region of the probe extension, preferably inthat the flexurally elastic part is implemented by drawing and has adiameter continuously tapering in the direction toward the contact shapeelement, wherein the length of the region running directly above thecontact shape element or the target mark to the region of the greaterdiameter is selected to be less than 2 mm, particularly 0.2 mm to 1.5mm, for use for scanning measurement, or greater than 2.5 mm,particularly 3 mm to 6 mm, for single-point measurement.

It is therefore preferably provided that two deflection signals,preferably deflection signals perpendicular to each other, are extractedfrom each of the images recorded by the laterally measuring opticalsensor and a third deflection signal, preferably perpendicular to thefirst two deflection signals, is provided by the vertically measuringdistance sensor, the deflection signals are preferably processed bymeans of the same or identical analysis unit and/or analysis software asis used for a conventional tactile probe in order to determine thedeflection of the contact shape element in 3D and to determine themeasurement points therefrom.

The idea is particularly emphasized that the recording of the image usedfor determining the deflection of the contact shape element in 3D ineach case and of the associated third deflection signal provided by thedistance sensor are recorded at the same point in time, controlled by atrigger line, as the recording of the positions of the measurement axesof the coordinate measuring machine.

For determining the lateral deflection of the contact shape element orthe target mark, the location or position of the image of the contactshape element or the target mark in the deflected state in the digitalimage recorded by the laterally measuring sensor is compared with thelocation or position in the non-deflected state. To this end, thelocation in the non-deflected state is calibrated in advance. Acharacteristic curve comprising the relationship of the position in theimage to the actual deflection must also be calibrated.

The invention proposes two fundamental methods for rapidly and preciselydetermining the orientation or position of the image of the contactshape element or the target mark in the digital image recorded by thelaterally measuring sensor. The first method is based on a contouranalysis, and the second on image correlation.

For the contour analysis, a contour is extracted from the digital imageby means of suitable mathematical algorithms. Measurement points arearranged in a row like beads along the curve of the edge and determinedto subpixel accuracy by interpolating the edge curve. For an individualimage capture of the round contact shape element, a circular contourhaving a plurality of measurement points thus arises. Subsequently, thecenter of the circular contour is typically used for determining theposition and can be determined using the method of the least square(“best-fit circle”). Alternatively, other features such as the centroidof the contour can be analyzed.

Image correlation makes it possible to locate any arbitrary objects inthe image. To this end, a reference image (template) of thenon-deflected contact shape element or the target mark is generated andsaved in advance. Said template is then searched for in the image whenmeasuring (the deflected contact shape element or target mark). Thelocation having the greatest similarity value corresponds to the centerposition of the contact shape element or the target mark. For imagecorrelation, the template is shifted across the image pixel by pixel. Asimilarity value is derived from the two at each point of the image. Thesimplest similarity value is the sum of the absolute difference of thetwo images. If the template matches the segment of the image, then thedifference between the two images is zero. The greatest match isachieved at said location. If, however, a change in the lightingintensity or brightness occurs in comparison with the condition when thetemplate was recorded, then the difference between the images can nolonger be zero using this method. A similarity value able to deal withthis condition is the normalized cross-correlation used as an exampleaccording to the following equation, wherein a type of normalization ofthe template or the image takes place:

${{ncc}\left( {i,j} \right)} = {\frac{1}{n}{\sum\limits_{{({x,y})} \in T}\left\lbrack {\frac{{T\left( {x,y} \right)} - \overset{\_}{T}}{\sqrt{s_{T}^{2}}} \cdot \frac{{B\left( {{i + x},{j + y}} \right)} - {\overset{\_}{B}\left( {i,j} \right)}}{\sqrt{s_{B}^{2}\left( {i,j} \right)}}} \right\rbrack}}$

Where ncc: cross-correlation value at i,j: image position; T: template;B: image; s_(T) ²: greyscale value variance of the template; s_(B) ²:greyscale value variance of the image region (covered by the template).

This method thereby achieves the object of precisely determining thedeflection even under poor imaging conditions or changed lightingconditions.

The result of the cross-correlation is a correlation matrix having thesame dimensions as the camera image and comprising correlation valuesbetween +1 and −1, wherein +1 means an exact match between the templateand the image. If the greyscale values are inverted, then the value is−1. The center position of the contact shape element or the target markis represented by the pixel coordinates having the greatest correlationcoefficient. Suitable interpolation methods such as linear or quadraticinterpolation allow analysis of the location with subpixel accuracy.Optimizations of the calculation-intensive image correlation using theknown standard methods are focused on reducing calculation times.Stepwise calculation in resolution stages using the pyramid method andthe use of simple test variables for filtering the maximum valuecandidates have potential, wherein unsuitable regions in the imagedetected by means of image analysis are excluded from the correlationanalysis.

According to a preferred solution according to the invention, thedeflection signals are extracted from the images recorded by means ofthe laterally measuring optical sensor in that the location of thecontact shape element or the target mark in each image is determined incomparison with the previously calibrated location in the non-deflectedstate, wherein the previously calibrated location and each particularlocation are determined by identifying the contour of the contact shapeelement or the target mark in the image and determining the centroid orcenter point of the contour, or are determined by means of correlationmethods, wherein the maximum correlation to a previously determinedtemplate of the image of the contact shape element or the target mark isdetermined, wherein the correlation is analyzed in a plurality ofdifferent locations of the template relative to each image.

It can therefore be characteristic that a cross-correlation is applied,wherein the fact that the template and the image were recorded underdifferent lighting, particularly brightness, is provided for as anadditional parameter, thus the template and/or image are normalizedaccordingly prior to determining the correlation.

Particularly emphasized is the idea that the correlation or thecorrelation coefficient is determined first at reduced resolution of theimage and/or template and a rough location of the contact shape elementor the target mark is determined and then at increased resolution in alimited image region around the roughly determined location, wherein themethod is preferably iteratively repeated at stepwise increasingresolution and stepwise limitation of the image region (pyramid method).

It is preferably provided that prior to determining a correlation,regions of the image excepted from the correlation analysis aredetermined, particularly using simple test parameters for filtering themaximum value candidates.

In order to achieve optimal alignment for the different probe extensionsused for single point measurements or scanning, for example, saidextensions are adjustable.

In a preferred refinement of the invention, the probe extension isadjusted relative to the laterally measuring optical sensor to this end,preferably in one, two, or three translational and/or one, two, or threerotational degrees of freedom.

According to a preferred solution according to the invention, the regionof the probe extension comprising the contact shape element is adjustedto an angle of 0°<Alpha<15° relative to the optical axis of thelaterally measuring optical sensor, in that

-   -   a fiber receptacle comprising a probe extension is used,        preferably changed in, said probe extension comprising a        corresponding preset bend between the region comprising the        contact shape element and the region of the fiber receptacle, or    -   a fiber receptacle comprising a fixing location implemented        accordingly is used, preferably changed in, or    -   the means for adjusting are adjusted accordingly,        and that the contact shape element or the target mark are        disposed in the focal region of the laterally measuring optical        sensor, preferably for measuring the roughness of a workpiece        surface.

Also characteristic is that a probe extension comprising a bend or apreferably star-shaped branching to a plurality of contact shapeelements between the contact shape element and the target mark is usedor changed in for measuring undercuts or other features inaccessible tostraight probe extensions.

The idea is particularly emphasized that the imaging scale whendeflecting in the vertical direction is held constant by using atelecentric optic having a fixed magnification or a telecentric zoomstage of a zoom optic, wherein the zoom optic preferably has a workingdistance adjustable independently of the imaging scale.

The precision of the measurement of the lateral deflection thereby doesnot change even if the captured contact shape element or target mark isdeflected vertically.

In a preferred refinement according to the invention, a zoom optic,preferably a zoom optic having a working distance adjustableindependently of the imaging scale, is used for determining the lateraldeflection, wherein a zoom stage is selected comprising an imaging scaleadapted to the diameter of the contact shape element or target markbeing captured in each case, particularly adapted so that the image ofthe contact shape element or target mark, including the maximumpermissible deflection thereof, is completely captured by the zoom opticand the resolution is maximized.

It is thereby ensured that contact shape elements or target marks ofdifferent sizes can be used, preferably by means of an automaticchanger, and can nevertheless be completely captured and measured. Theadaptation is preferably implemented such that a zoom stage is selectedin which the entire image of the contact shape element or the targetmark can just be captured when providing for the maximum permissibledeflection. This ensures the maximum possible resolution and thereforethe precision of the lateral measurement.

According to a preferred solution according to the invention, thevertically measuring optical distance sensor is a sensor using theFoucault principle, wherein a lighting source illuminates only a limitedpart of the aperture of the optic used on the object for imaging, and/orwherein a linear or planar detection unit such as a position-sensitivediode (PSD) or camera is used for determining the location of thelighting reflected by the workpiece, wherein the location is preferablydetermined by means of a camera, in that

-   -   a differential signal is determined from the sum signals,        preferably the sum signals of the measured intensities of the        individual light-sensitive elements of the detection unit from        at least two different regions of the camera, preferably equally        sized regions adjacent to each other in the center of the camera        area, and/or    -   the beam centroid, preferably the photometric center, is        determined by analyzing the intensities of the individual        light-sensitive elements of at least one partial region of the        camera area.

In addition to the previous explanations of said preferred refinement ofa Foucault distance sensor, when using a camera as the detection unit itis proposed that the location of the lighting reflected by the workpieceis calculated, starting from a separate lighting source of the Foucaultsensor, from the intensity distribution recorded using the variouslight-sensitive elements of the camera. The result of the difference isa signal passing through zero and used as the center of the measurementrange. The centroid of the beam is used in the regions wherein thedifference signal is saturated, that is, at least one of the selectedregions is no longer illuminated, or as additional monitoring. In orderto avoid blooming in the camera, the integration time of the camera isset correspondingly low. Due to the reading frequency thus achieved andsupported by the limitation of lines or columns, as previouslyexplained, a plurality of images recorded one after the other can besummed in order to achieve a high signal-to-noise ratio. The integrationtime adjustment is also used for regulating to a constant lightintensity in order to implement an adjustment to a different surfacereflection levels or surface tilts.

The tactile/optical sensor is preferably integrated in a coordinatemeasuring machine, preferably in a multisensor coordinate measuringmachine, together with additional sensors, preferably tactile, optical,or computed-tomography sensors, preferably such that the laterallymeasuring optical sensor and the vertically measuring optical distancesensor are operated independently of the tactile/optical sensor.

This means, for example, that the laterally measuring optical sensor andthe vertically measuring optical distance sensor can be usedalternatively for measuring the workpiece surface when the probeextension is set aside, that is, when the fiber receptacle, adjustingunit, or mount are set aside.

The invention further relates to a method for determining geometricfeatures and structures on a workpiece by means of a tactile/opticalsensor comprising at least a laterally measuring optical sensor,preferably an image processing sensor, preferably a vertically measuringoptical distance sensor, and an at least partially flexurally elasticprobe extension, at least the following emerging from the probeextension: a contact shape element deflecting when contacting theworkpiece, and preferably at least one target mark associated with thecontact shape element and deflecting when the contact shape elementcontacts the workpiece, the lateral deflection of the contact shapeelement or of the target mark perpendicular to the optical axis of thelaterally measuring optical sensor being captured by means of the same,and the vertical deflection of the contact shape element or of thetarget mark along the optical axis of the laterally measuring opticalsensor being captured by means of the distance sensor, characterized inthat a probe extension emerging from a fiber receptacle to which aflexurally elastic part is directly or indirectly connected is used, towhich part the contact shape element or optionally the target mark isdirectly or indirectly connected, wherein the part of the probeextension running between the optional target mark, if present, and thecontact shape element is flexurally rigid relative to the flexurallyelastic part. that the probe extension is changed in manually orautomatically by means of which a plurality of measurement points,preferably offset from each other, on the workpiece can each bedetermined in scanning mode, in that the following steps are performed:

-   -   the contact shape element and workpiece are displaced toward        each other relative to each other until a predefined deflection        of the contact shape element or the target mark has been        achieved    -   the contact shape element and workpiece are displaced relative        to each other along a path, wherein the contact shape element        and the workpiece remain in contact, and wherein the deflection        of the contact shape element and/or the target mark is        determined cyclically during the displacement    -   the contact shape element and workpiece are displaced relative        to each other away from each other at least until the contact        shape element or the target mark is no longer deflected    -   the plurality of measurement points are calculated from the        plurality of determined deflections and the location of the        tactile/optical sensor relative to the workpiece in each case,        preferably using the positions of the measurement axes of a        coordinate measuring machine.        a target path such as a spline is defined for the path and is        formed by one or more prescribed curves in space, wherein the        curves are defined preferably based on previously measured        points and/or a model such as a CAD model of the workpiece        and/or from basic geometric shapes such as the line, line        segment, circle, segment of a circle, or segment of a helix, and        the path either corresponds to the target path (uncontrolled        scanning) or follows the target path providing for the        deflection of the contact shape element and/or the target mark,        preferably in at least two coordinate directions defined by a        scanning plane (controlled scanning), and the deflection during        the displacement on the path is controlled between a minimum and        a maximum value about a target deflection by displacing        corresponding coordinate measuring machine axes, wherein the        control preferably takes place perpendicular to a scanning plane        or in the two spatial directions within the scanning plane or in        all three spatial directions.

The invention further relates to a method for determining geometricfeatures and structures on a workpiece by means of a tactile/opticalsensor comprising at least a laterally measuring optical sensor,preferably an image processing sensor, preferably a vertically measuringoptical distance sensor, and an at least partially flexurally elasticprobe extension, at least the following emerging from the probeextension: a contact shape element deflecting when contacting theworkpiece, and preferably at least one target mark associated with thecontact shape element and deflecting when the contact shape elementcontacts the workpiece, the lateral deflection of the contact shapeelement or of the target mark perpendicular to the optical axis of thelaterally measuring optical sensor being captured by means of the same,and the vertical deflection of the contact shape element or of thetarget mark along the optical axis of the laterally measuring opticalsensor being captured by means of the distance sensor, characterized inthat a probe extension emerging from a fiber receptacle to which aflexurally elastic part is directly or indirectly connected is used, towhich part the contact shape element or optionally the target mark isdirectly or indirectly connected, wherein the part of the probeextension running between the optional target mark, if present, and thecontact shape element is flexurally rigid relative to the flexurallyelastic part. that the probe extension is changed in manually orautomatically by means of which a plurality of measurement points,preferably offset from each other, on the workpiece can each bedetermined in scanning mode, in that the following steps are performed:

-   -   the contact shape element and workpiece are displaced toward        each other relative to each other until a predefined deflection        of the contact shape element or the target mark has been        achieved    -   the contact shape element and workpiece are displaced relative        to each other along a path, wherein the contact shape element        and the workpiece remain in contact, and wherein the deflection        of the contact shape element and/or the target mark is        determined cyclically during the displacement    -   the contact shape element and workpiece are displaced relative        to each other away from each other at least until the contact        shape element or the target mark is no longer deflected    -   the plurality of measurement points are calculated from the        plurality of determined deflections and the location of the        tactile/optical sensor relative to the workpiece in each case,        preferably using the positions of the measurement axes of a        coordinate measuring machine.        the path is defined by a starting point and an ending point, and        preferably by one or more intermediate points, and preferably by        a starting direction and/or a scanning plane, and that between        the defined points the path is determined by providing for the        deflection of the contact shape element and/or target mark        (controlled scanning) by the location of the workpiece surface        being contacted, the deflection during the displacement on the        path is controlled between a minimum and a maximum value about a        target deflection by displacing corresponding coordinate        measuring machine axes, wherein the control preferably takes        place perpendicular to a scanning plane or in the two spatial        directions within the scanning plane or in all three spatial        directions. when controlling in the two spatial directions        within the scanning plane, the control takes place in the        direction of the deflection, preferably in the direction of the        deflection projected into the scanning plane, and the        displacement along the path within the scanning plane takes        place perpendicular to the deflection projected into the        scanning plane, wherein the sense of direction of the        displacement is defined so as to form the smaller angle to the        previous direction of displacement.

The invention further relates to a method for determining geometricfeatures and structures on a workpiece by means of a tactile/opticalsensor comprising at least a laterally measuring optical sensor,preferably an image processing sensor, preferably a vertically measuringoptical distance sensor, and an at least partially flexurally elasticprobe extension, at least the following emerging from the probeextension: a contact shape element deflecting when contacting theworkpiece, and preferably at least one target mark associated with thecontact shape element and deflecting when the contact shape elementcontacts the workpiece, the lateral deflection of the contact shapeelement or of the target mark perpendicular to the optical axis of thelaterally measuring optical sensor being captured by means of the same,and the vertical deflection of the contact shape element or of thetarget mark along the optical axis of the laterally measuring opticalsensor being captured by means of the distance sensor, characterized inthat a probe extension emerging from a fiber receptacle to which aflexurally elastic part is directly or indirectly connected is used, towhich part the contact shape element or optionally the target mark isdirectly or indirectly connected, wherein the part of the probeextension running between the optional target mark, if present, and thecontact shape element is flexurally rigid relative to the flexurallyelastic part, the deflection signals are extracted from the imagesrecorded by means of the laterally measuring optical sensor in that thelocation of the contact shape element or the target mark in each imageis determined in comparison with the previously calibrated location inthe non-deflected state, wherein the previously calibrated location andeach particular location are determined by identifying the contour ofthe contact shape element or the target mark in the image anddetermining the centroid or center point of the contour, or aredetermined by means of correlation methods, wherein the maximumcorrelation to a previously determined template of the image of thecontact shape element or the target mark is determined, wherein thecorrelation is analyzed in a plurality of different locations of thetemplate relative to each image, a cross-correlation is applied, whereinthe fact that the template and the image were recorded under differentlighting, particularly brightness, is provided for as an additionalparameter, thus the template and/or image are normalized accordinglyprior to determining the correlation.

The invention further relates to a method for determining geometricfeatures and structures on a workpiece by means of a tactile/opticalsensor comprising at least a laterally measuring optical sensor,preferably an image processing sensor, preferably a vertically measuringoptical distance sensor, and an at least partially flexurally elasticprobe extension, at least the following emerging from the probeextension: a contact shape element deflecting when contacting theworkpiece, and preferably at least one target mark associated with thecontact shape element and deflecting when the contact shape elementcontacts the workpiece, the lateral deflection of the contact shapeelement or of the target mark perpendicular to the optical axis of thelaterally measuring optical sensor being captured by means of the same,and the vertical deflection of the contact shape element or of thetarget mark along the optical axis of the laterally measuring opticalsensor being captured by means of the distance sensor, characterized inthat a probe extension emerging from a fiber receptacle to which aflexurally elastic part is directly or indirectly connected is used, towhich part the contact shape element or optionally the target mark isdirectly or indirectly connected, wherein the part of the probeextension running between the optional target mark, if present, and thecontact shape element is flexurally rigid relative to the flexurallyelastic part, the region of the probe extension comprising the contactshape element is adjusted to an angle of 0°<α<15° relative to theoptical axis of the laterally measuring optical sensor, in that

-   -   a fiber receptacle comprising a probe extension is used,        preferably changed in, said probe extension comprising a        corresponding preset bend between the region comprising the        contact shape element and the region of the fiber receptacle, or    -   a fiber receptacle comprising a fixing location implemented        accordingly is used, preferably changed in, or    -   the means for adjusting are adjusted accordingly,        and that the contact shape element or the target mark are        disposed in the focal region of the laterally measuring optical        sensor, preferably for measuring the roughness of a workpiece        surface.

In a preferred refinement according to the invention, the brightness ofthe light emitted by the contact shape element or target mark isdetermined by the camera of the image processing sensor and is regulatedto a constant value by controlling the light source for illuminating thecontact shape element or the target mark, preferably wherein the valueis defined beforehand or is defined using the first image recorded formeasuring by means of the image processing sensor.

Regulating the brightness of the image of the image processing sensorensures that the imaging of the contact shape element or the target markused for analyzing the lateral deflection occurs reproducibly in theso-called self-illumination mode. Particularly in case of deep insertionin a tight hole, at least slight shadowing occurs and can be thereby atleast partially eliminated. Even deviations in the brightness in astandard condition present when calibrating the tactile/optical sensor,however, can bring about measurement deviations. If the value is thusdetermined in advance when calibrating and then adjusted for eachmeasurement, that is, correspondingly controlled, then constant lightconditions are present and particularly reproducibly precisemeasurements are possible.

The invention thus proposes devices and methods for tactile/opticalsensors proposing solutions for:

-   -   Measuring using scanning methods, particularly the potential for        switching between single point measuring and scanning        arbitrarily and scanning on specified paths or freely (from a        starting to an ending point) and scanning in a controlled or        uncontrolled manner.    -   Simple and reproducible adjusting of the probe extension,    -   Measuring at an adjustable tilt of the probe extension,        particularly a tilt for setting once or set once, and using for        measuring surfaces of different orientations, for example for        roughness measurements, and corresponding changeout interfaces        therefore ensuring reproducible location and tilt of the probe        extension at different tilt directions,    -   A further changeout interface making an additional adjusting of        different probe extensions unnecessary,    -   Light sources integrated in interchangeable fiber holders (fiber        receptacles) for illuminating the probe extension,    -   Measuring undercuts, and undercuts at arbitrary orientation, at        high precision (without using rotary joints or rotary/tilting        joints),    -   Implementing a precisely constant imaging scale when deflecting        in the direction of the optical axis of the optic used for        optically capturing the deflection of the contact shape element        or the target mark of the probe extension,    -   Implementing an adjustable precision for the deflection        measurement,    -   Arbitrarily large measurement range or high precision for        determining vertical deflection.    -   A large measurement range of the vertically measuring sensors,    -   Using tactile/optical sensors analogously to tactile sensors,    -   Rapidly and precisely determining the lateral defection of the        contact shape element or target mark under poor imaging        conditions,        and able to be provided in one or as few different arrangements        as possible.

The object of an independent invention is to provide a method forproducing the probe extension, including the contact shape element andoptionally the target mark, by means of which a specified diameter, atleast in the region of the probe extension facing the workpiece, andoptionally a specified shape such as a bend for the probe extension, anda specified diameter for the contact shape element and optionally thetarget mark can be implemented having high precision, in order to usethe probe extension for precisely measuring geometric features orstructures on a workpiece by means of a tactile/optical sensor loaded ina coordinate measuring machine.

The invention thus further relates to a method for producing a probeextension, a contact shape element emerging from the probe extension,and preferably a target mark for a tactile/optical sensor for use in acoordinate measuring machine for measuring geometric features andstructures on a workpiece.

In an independent solution according to the invention, a taperingdiameter of the probe extension is produced by drawing under theinfluence of heat, preferably by means of laser, electric arc, or hotwire, and the contact shape element and/or target mark are produced byfusing and preferably by means of cohesion or adhesion, from one or morefiber pieces, preferably glass fiber pieces.

According to an independently protected proposal, the invention furtherrelates to a method for producing a probe extension, a contact shapeelement emerging from the probe extension, and preferably a target markfor a tactile/optical sensor for use in a coordinate measuring machinefor measuring geometric features and structures on a workpiece, theprobe extension being at least one segment of a fiber, particularly anoptical glass fiber, or a fiber pieces such as a glass fiber piece, andcharacterized in that the diameter of at least one segment of the fibersegment is tapered by drawing under the influence of heat, such as alaser, arc, or heating wire, and that the contact shape element and/orany present target mark are produced by melting and preferably byutilizing cohesion or adhesion.

The heat source is preferably such that a high temperature is achievedin as small a local environment as possible, such as is possible bymeans of plasma or electric arc, a laser beam, or a high-powered hotwire, for example. The regions of the glass fiber are guided to the heatsource (e.g., for adhering or splicing) or intentionally guided alongthe same (e.g., for reducing or drawing, also known as “tapering”) inorder to locally melt said regions.

Fiber pieces having multilayer construction made of a glass core,particularly a quartz glass core, a cladding surrounding said core, asilicone layer surrounding said cladding, and a plastic layer in turnsurrounding said layer and preferably made ofethylene-tetrafluoroethylene such as Tefzel (registered trademark ofDuPont). The cladding can also be made of glass or quartz glass and canthen in general no longer be removed from the quartz glass core, or of adifferent material and can be removed from the quartz glass core. Whendrawing, only the layers made of glass can remain, as any other layerspresent would burn. The silicone layer and plastic layer, and anycladding not made of glass, are therefore removed from the regionintended for drawing. When drawing, a tapering of the diameter occursdue to the principle, wherein said diameter continuously decreases alongthe fiber. If the reduction occurs at an approximately constant rate,then the preferred conical shape of the drawn fiber piece arises. Thedrawn fiber piece is connected to a non-drawn region of the probeextension. The contact shape element is attached or formed or producedat the end facing away from the sensor, that is, in the region intendedto be inserted into the workpiece. After drawing the fiber, the drawnregion having the tapering diameter in particular can be seen as theflexurally elastic region of the probe extension. The non-drawn partpractically does not flex at all when the contact shape element isdeflected, due to the greater diameter thereof.

A further process is cutting off a drawn fiber, for example, also knownas cleaving. Alternatively, a tapered fiber is broken. A thick region isformed on a drawn, that is, tapered and broken or cut-off end of thefiber, for example, by means of a particular method, in that the breakor cut point is heated by an electric arc. The surface tension of themolten glass causes a spherical drop to form, implementing the contactshape element or the target mark. In the second case, one or moreseparate fiber pieces are adhered to the target mark by adhesion, thatis, again by local heating, a contact shape element being attached tothe opposite end of said piece, the contact shape element in turn beingproduced by means of the previously described method for forming a thickregion. Alternatively to thickening, a contact shape element can also beproduced separately and adhered to the end of the fiber, again by localheating. The separate fiber piece having a contact shape element runs inthe direction of the segment of the probe extension connected to thetarget mark, for example, that is, in the direction of the optical axisof the laterally measuring sensor, or in the modified direction aspreviously described. A plurality of separate fiber pieces form a starshape, for example.

The idea is therefore particularly preferred that the contact shapeelement or the target mark at the end of the probe extension having atapered diameter is produced by thickening the probe extension duringthe melting operation, or a separately produced contact shape element ortarget mark is adhered.

The target mark can alternatively be produced by thickening within theprobe extension itself, in that said probe extension is upset whilebeing heated.

In a particular embodiment according to the invention, therefore, thetarget mark is produced within the part of the probe extension having atapered diameter by thickening the probe extension during the meltingoperation, preferably by upsetting.

According to the invention, one or more separately produced fiber piecesare adhered to the target mark and run in the direction of the segmentof the probe extension emerging from the target mark or in one or moremodified directions, wherein the contact shape element or each contactshape element emerges from the end of the fiber piece or pieces oppositethe adhesion.

In the previously described embodiment of the 2D sensor, the probeextension must be bent by approximately 90°. To this end, according to afirst embodiment of the invention, the weight of the fiber itself isused and the fiber is guided past in the heat source in a definedmanner. In order to produce a uniform radius, the fiber is then guidedacross a ceramic bar lowering in a defined motion. A vertical motion isthereby superimposed on a horizontal one. The motion of the fibersegment—also called a fiber piece—and support element such as a ceramicbar are mutually tuned, wherein the distances traveled relative to eachother are correlated, particularly at a constant ratio, particularlyone. The bar-shaped support element extends in the direction of thelongitudinal axis perpendicular to the direction of motion of the fibersegment, that is, in the longitudinal axis thereof running in the regionof the support element.

Therefore, preferably the probe extension is bent under the influence ofheat and utilizing gravity, preferably by 90° or by 85° to 95°, whereinthe probe extension is guided past the heat source by means of a feedingmotion, the bending is preferably performed at a constant radius in thatthe fiber piece is supported over a support bar such as a cylindricalceramic bar downstream of the heat source, said bar undergoing at leasta vertical displacement, preferably at least at times a superimposedvertical and horizontal displacement, wherein particularly the feedingmotion of the probe extension and the displacement of the support barare mutually tuned at a correlated ratio, preferably a constant ratio.

In a second embodiment of the invention, the bend is produced in thatthe fiber itself is not plastically deformed; instead the rigid sleeve,such as the metal tube and in general the hollow cylinder indicatedabove. The non-bent region of the fiber piece is then placed, forexample inserted, into the metal tube. The fiber piece thereby followsthe shape of the tube, previously bent by approximately 90°. The drawnregion of the fiber piece remains outside of the tube. In the non-drawnregion, the plastic layer and silicon layer are preferably not removed,because the fiber could otherwise break during inserting and deflectingin the tube. The tube preferably runs past the bend point into the fiberholder. On the contact shape element side, the non-drawn regionprotrudes out of the tube, for example a few millimeters, for example 1mm to 10 mm, for particular shapes also up to 50 mm to 100 mm, beforethe drawn region begins. At the point that the non-drawn region exitsthe tube on the contact shape element, said region is adhered to thetube.

In a particular embodiment of the invention, the probe extension isinserted into the interior of a hollow cylinder, at least in segments,wherein the hollow cylinder comprises a bend of 85° to 95°, preferably90°, wherein preferably only non-drawn regions of the probe extensionrun within the hollow cylinder and preferably the probe extension andhollow cylinder are adhered to each other at the exit point of the probeextension out of the hollow cylinder facing toward the contact shapeelement.

In the case of the 3D sensor, according to the invention a target markassociated with the distance sensor, such as a reflector, is attached tothe end of the probe extension facing away from the contact shapeelement. This is done preferably by adhesion, particularly under theinfluence of heat. The end of the probe extension facing away from thecontact shape element is thereby not drawn.

The idea is particularly emphasized that fiber pieces constructed inmultiple layers are used, preferably comprising a cladding about a glasscore, preferably a quartz glass core, preferably a quartz glasscladding, and at least in segments having a silicone layer and a plasticlayer, preferably made of ethylene tetrafluoroethylene such as Tefzel(registered trademark of DuPont), and preferably only the regions madeof glass are subjected to the influence of heat.

In order to perform the previously explained production method at highprecision, according to the invention, the process iscomputer-controlled. Particularly the feeding motion and aligning of thefiber can then take place quickly and precisely. The aligning inparticular is needed during adhesion. A defined alignment of the fiberis also needed when drawing and cutting the fiber. Said processes arealso monitored optically by means of a camera or image processing sensorand controlled accordingly. According to the invention, cleaning bymeans of plasma is performed before adhering.

According to a preferred solution according to the invention, themelting operation, drawing operation, and adhering operation, andpreferably the feeding motion, cutting operation, and operation forcleaning the fiber ends by means of plasma are controlled by a computer,preferably in that computer-controlled translational and rotationalalignment of the ends to be adhered takes place prior to adhering atleast in the two directions running perpendicular to the fiber directionand preferably in the two tilting directions about said perpendiculardirections.

The production of the probe extension can also be characterized bymonitoring by means of a camera, preferably an image processing sensor,and/or controlling by means of signals generated by means of the camera,preferably by an image processing sensor.

According to an idea having independent protection, a method forproducing a probe extension for a tactile/optical sensor is provided,wherein the probe extension is designed for being received in a fiberreceptacle, wherein the method is characterized in that a planar flatarea is formed in regions on the outside of the probe extension at theend of the probe extension facing away from the contact shape element,preferably the outside of the hollow cylinder receiving the probeextension.

The idea is thereby particularly preferred that the normal direction ofthe flat area is parallel to the direction of the region of the probeextension running parallel to or along the optical axis, and that thehollow cylinder is bent by 90°, preferably by bending in a fixture,wherein the flat area of the hollow cylinder is placed against a contactsurface and the bending direction is aligned to the normal of thecontact surface.

A further object of an independent invention is a device and a methodfor using a tactile/optical sensor for measuring surface point on aworkpiece.

The independent invention particularly relates to a device fordetermining geometric features and structures on a workpiece by means ofa tactile/optical sensor comprising a mounting element for an at leastpartially flexurally elastic probe extension, at least the followingemerging from the probe extension: a contact shape element fordeflecting when contacting the workpiece and a first target markassociated with the contact shape element for deflecting when thecontact shape element contacts the workpiece, such that the deflection,preferably the lateral deflection, thereof can be captured by means of afirst laterally measuring optical sensor, preferably an image processingsensor,

Tactile/optical sensors are described in the following specifications ofthe applicant.

EP0988505 describes a method and a device wherein a probe element (firsttarget mark) and optionally a further target mark emerge from a probeextension via a flexurally elastic shaft, the coordinates thereof whendeflected being determined by means of an optical sensor.

A similar sensor is described in EP 1 071 921, wherein the contact forceis adjusted by means of the rigidity of the flexurally elastic shaft, inthat solely the bending length 1 is varied.

An opto-mechanical interface having an adjusting device for acorresponding sensor is described in EP 1 082 581.

DE 198 24 107 describes the use of a corresponding sensor for a surfaceprofiling method.

A corresponding sensor is operated on a rotating or pivoting joint inDE10 2004 022 314.

Finally, DE 10 2010 060 833 describes a tactile/optical sensor wherein,in addition to determining the position of a contact shape element or atleast a target mark associated therewith in the X and/or Y direction ofthe coordinate measuring machine using a first sensor, a second sensoralso determines the Z-direction, wherein at least one flexibleconnecting element is used for mounting the contact shape element andthe target mark in a mounting element, said connecting element beingpenetrated by the beam path of the first sensor in the beam direction,wherein the at least one flexible connecting element is transparentand/or is severely defocused with respect to the first sensor.

Full reference is made to the disclosed contents of all previously namedspecifications of the applicant.

The object of the present invention is to implement precise measuringeven for features accessible only by means of a relatively long and thinprobe pin or a so-called probe extension having a length of preferablygreater than five millimeters and a diameter of preferably less than 0.5mm, wherein low contact forces must be ensured in order to protect theworkpiece against damage and preferably also very small dimensions inthe range of less than 0.5 mm in diameter should be achieved for thecontact shape element used for contacting, in order to ensure highstructural resolution, for example, or to enable measuringdifficult-to-access features such as holes having a small diameter. Theprobe pin or probe extension can thereby run in the direction of theoptical axis of the measurement system used for measuring the deflectionof the contact shape element or a target mark associated therewith, orcan also protrude laterally (L-probe). A plurality of lateralprotrusions in different directions and lengths (star probe) havinggreat lengths from several millimeters to a few centimeters shall alsobe able to be implemented.

In order to achieve the object, the contact shape element must beattached to a long probe extension. If the contact shape element is theninserted very far into the workpiece, such as into a hole, then theimage on the optically laterally measuring image processing sensor ispartially shadowed by the workpiece, giving rise to measurementdeviations. As an improvement, EP 0 988 505 therefore proposesintegrating an additional target mark in the probe extension above thecontact shape element, said mark always remaining away from theworkpiece, such as slightly above a hole. Said mark can then be capturedby the image processing sensor unhindered. A previous disadvantagethereof, however, is that the probe extension is made of a single piece,wherein the entire probe extension must be very thin in order to achievea low contact force (and associated low risk of damaging the workpiece),typically less than 0.5 mm in diameter, and implemented as a glass orplastic fiber, for example. When making contact, the probe extensionthereby bends, wherein only a portion of the deflection of the contactshape element is transferred to the target mark, said portion decreasingas the length of the probe extension increases. The sensitivity of theentire system is thereby reduced, that is, the signal-to-noise ratiobecomes lower the greater the distance between the contact shape elementand the target mark. Said problem also cannot be solved in that agreater diameter is selected for the probe extension, as otherwisemeasurements can no longer be taken in holes having a very smalldiameter, such as injection orifices in fuel injectors. In addition,very small diameters for the probe extension in conjunction with theselected material can lead to lower rigidity and therefore to so-calledshaft contact, wherein the shaft makes contact with the workpiece andcauses erroneous measurement results.

At least some considerations of said object are substantially achievedby a device and a method using a tactile/optical sensor comprising aprobe pine or a probe extension having a first region having higherrigidity, such as a first elastic modulus, and a second region havinglower rigidity, such as a second elastic modulus, wherein optionally thefirst elastic modulus is greater than the second elastic modulus.Dimensioning accordingly results in favorable conditions fortransferring the deflection of the contact shape element to thedeflection of the target mark captures by means of the measurementsystem or sensor or plurality of measurement systems or sensors,particularly if the first region of greater rigidity is disposed betweenthe contact shape element and the target mark or marks. The secondregion of lower rigidity extends at least partially between theattachment or mounting element of the probe extension on thetactile/optical sensor and thus on the measuring machine, such as acoordinate measuring machine, and the or one of the target marks or theconnection between the contact shape element and the target mark or theconnection between the plurality of target marks, thereby achieving alow contact force.

The second region of lower rigidity begins at the mounting element ornear the mounting element and ends, in a first preferred solutionaccording to the invention, at the first target mark or one of theplurality of target marks, if present. If a plurality of target marksare present then the second region particularly ends after the targetmark nearest to the mounting element.

In an alternative solution according to the invention, the second regionends at the connection between the target mark and the contact shapeelement or the connection between the plurality of target marks, thatis, at the first region of higher rigidity.

The first region of higher rigidity can thus also extend between theplurality of target marks. Thus a plurality of target marks are alsoprovided according to the invention. A second target mark is therebyprovided for capture by a second measurement system, particularly adistance sensor, capturing the deflection of the second target markperpendicular, hereafter referred to as the vertical deflection, to thedeflection of the first target mark, hereafter referred to as thelateral deflection. The first region of higher rigidity then extendsbetween the contact shape element and the first target mark and thefirst and second and optionally further target marks. It is therebyachieved that the deflection of the contact shape element is transferredas fully as possible to all target marks in use.

As a refinement of said idea according to the invention, thedimensioning of the first region is implemented so that only onecomponent of the deflection of the contact shape element, for examplethe vertical deflection, is transferred as fully as possible to aparticular target mark, for example the second target mark. In general,the component determined by the measurement system associated with thecorresponding target mark should be transferred as fully as possible tosaid particular target mark.

According to DE102010060833, for example, at least one flexibleconnecting element is used for attaching the contact shape element andthe optionally at least one target mark associated therewith in amounting element, said connecting element being penetrated by the beampath of the first sensor in the beam direction and wherein at least oneflexible connecting element is transparent and/or is disposed severelyout of focus with respect to the first measurement system or the firstsensor. According to the present invention, said flexible connectingelements can be seen as part of the probe extension and preferablyimplement the or part of the second region of lower rigidity accordingto the invention.

A region of higher rigidity is particularly understood as a regiondimensioned with respect to the region of lower rigidity such that,according to the formula from EP 1 071 921 B1:

$F = \frac{3 \cdot E \cdot f \cdot I}{l^{3}}$where F is the contact force and E is the elastic modulus, l is theeffective length and I is the axial moment of area (or moment ofinertia) of the region of the probe extension under consideration, and fis the deflection of the contact shape element, the parameters E, l, andI, preferably the elastic modulus E, are adjusted accordingly, forexample by selecting different materials for the two regions, such thatwhen a contact force acts, that is, when the contact shape elementcontacts the workpieces, deformation is nearly completely avoided,preferably limited to a value of no greater than 10%, particularlypreferably no greater than 1%.

The invention thus further relates to a device for determining geometricfeatures and structures on a workpiece by means of a tactile/opticalsensor comprising a mounting element for an at least partiallyflexurally elastic probe extension, at least the following emerging fromthe probe extension: a contact shape element for deflecting whencontacting the workpiece and a first target mark associated with thecontact shape element for deflecting when the contact shape elementcontacts the workpiece, such that the deflection, preferably the lateraldeflection, thereof can be captured by means of a first laterallymeasuring optical sensor, preferably an image processing sensor.

The object of the invention is achieved in that the probe extensioncomprises a higher rigidity in a first region disposed at least betweenthe contact shape element and the first target mark than in a secondregion disposed between the mounting element and the first target mark,or between the mounting element and the first region.

The invention further relates to a device for determining geometricfeatures and structures on a workpiece by means of a tactile/opticalsensor, the first and preferably a second target mark emerging from theat least partially flexurally elastic probe extension, the first and, ifpresent, the second target mark being associated with the contact shapeelement for deflecting when the contact shape element contacts theworkpiece, the deflection of the first and, if present, the secondtarget mark perpendicular or nearly perpendicular to the deflection ofthe first target mark captured by means of the first optical sensorbeing determined by means of a second optical sensor, preferably anoptical distance sensor, characterized in that the first region ofgreater rigidity is disposed between the contact shape element and thefirst target mark and, if the second target mark is present, between thefirst and second target marks, and if the second mark is present thesecond region of lower rigidity is disposed between the mounting elementand the region between the first and second target marks.

In a first preferred refinement according to the invention, the firstand preferably also a second target mark emerge from the at leastpartially flexurally elastic probe extension, the first and preferablyalso the second target mark being associated with the contact shapeelement for deflecting when the contact shape element contacts theworkpiece, the deflection of the first or preferably the second targetmark perpendicular or nearly perpendicular to the deflection of thefirst target mark captured by means of the first optical sensor beingdetermined by means of a second optical sensor, preferably an opticaldistance sensor, wherein the first region of greater rigidity isdisposed between the contact shape element and the first target markand, if a second target mark is present, between the first and secondtarget mark, and, if a second target mark is present, preferably thesecond region of lower rigidity is disposed between the mounting elementand the region between the first and the second target marks.

The idea is particularly emphasized that at least one part of the probeextension is implemented as one or more flexible connecting elements forattaching the contact shape element and the first and optionally secondtarget mark to a mounting element, said connecting elements beingpenetrated by the beam path of the first sensor in the beam direction,and that the at least one flexible connecting element is transparentand/or is disposed severely out of focus with respect to the firstsensor.

According to a particularly preferred solution according to theinvention, the first region has a greater elastic modulus E than thesecond region, for example due to selecting appropriately differentmaterials or hardening the first region.

It is therefore also characteristic that the first region is made of atleast one of the materials steel, diamond, graphene, or tungsten, and/orthe second region is made of a material having a lesser elastic modulussuch as glass, glass fiber, plastic, or plastic fiber such aspolyethylene, polypropylene, polyvinylchloride, orpolyethyleneterephthalate.

In a second preferred refinement according to the invention, the firstregion has a greater moment of area I, preferably a greater thickness,and/or a lesser length 1 than the second region.

According to an embodiment of the invention, the contact shape elementis spherical or nearly spherical or disc-shaped in design at the end ofthe probe extension on the object side, and the first target mark isspherical or ball-shaped or nearly spherical or ellipsoidal orcylindrical or rectangular or nearly rectangular or disc-shaped ornearly disc-shaped or is implemented as a thickening of the probeextension.

The probe extension is preferably divided into a plurality of singleparts, particularly into the first and second regions, and the singleparts are connected to each other and/or to the first and/or the secondtarget mark and/or to the contact shape element by adhering or weldingor splicing, and/or form units by splicing or forming.

The idea is particularly emphasized that the probe extension is L-shapedor star-shaped in design, wherein one contact shape element is presentat each end of the star.

According to an embodiment of the invention, the tactile/optical sensoris integrated as a sensor in a coordinate measuring machine, preferablya multisensor coordinate measuring machine, together with additionalsensors.

The present invention relates to a method for determining geometricfeatures and structures on a workpiece by means of the tactile/opticalsensor according to the invention.

The method according to the invention is further characterized in thatthe tactile/optical sensor is used in a coordinate measuring machine,preferably a multisensor coordinate measuring machine together withadditional sensors.

An independent invention relates to a device and a method fortactile/optical measuring of geometric features and structures on aworkpiece.

An independent invention further relates to the coating of atactile/optical sensor for measuring geometric features and structure onworkpieces, wherein an improved coating is used.

The independent invention particularly relates to a method and a devicefor determining geometric features and structures on a workpiece bymeans of a tactile/optical sensor at least made of an at least partiallyflexurally elastic probe extension, at least the following emerging fromthe probe extension: a contact shape element for deflecting whencontacting the workpiece, and a target mark associated with the contactshape element for deflecting when the contact shape element contacts theworkpiece such that the lateral deflection thereof, perpendicular to theoptical axis of a laterally measuring optical sensor can be captured bymeans of the optical sensor, preferably an image processing sensor.

Tactile/optical sensors are described in the following specifications ofthe applicant.

EP 0 988 505 describes a method and a device wherein a probe element(first target mark) and optionally a further target mark emerge from aprobe extension via a flexurally elastic shaft, the coordinates thereofwhen deflected being determined by means of an optical sensor.

A similar sensor is described in EP 1 071 921, wherein the contact forceis adjusted by means of the rigidity of the flexurally elastic shaft, inthat solely the bending length 1 is varied.

An opto-mechanical interface having an adjusting device for acorresponding sensor is described in EP 1 082 581.

DE 198 24 107 describes the use of a corresponding sensor for a surfaceprofiling method.

A corresponding sensor is operated on a rotating or pivoting joint in DE10 2004 022 314.

DE 10 2010 060 833 describes a tactile/optical sensor wherein, inaddition to determining the position of a contact shape element or atleast a target mark associated therewith in the X and/or Y direction ofthe coordinate measuring machine using a first sensor, a second sensoralso determines the Z-direction, wherein at least one flexibleconnecting element is used for mounting the contact shape element andthe target mark in a mounting element, said connecting element beingpenetrated by the beam path of the first sensor in the beam direction,wherein the at least one flexible connecting element is transparentand/or is severely defocused with respect to the first sensor.

Finally, PCT/EP01/010826 describes coating a probe element or probeextension on the side facing away from the sensor in order to generate aluminous mark in the interior of the probe element by bundling theradiation reflected at the coating, said radiation being introduced intothe interior of the shaft of the probe element or probe extension, thelength thereof being measured, and a mark associated with the probeelement and formed by a darkened region of the luminous shaft of theprobe element.

Full reference is made to the disclosed contents of all previously namedspecifications of the applicant.

The object of the present invention is to implement precise measuring offeatures difficult to access, particularly in holes or similar recessesmore than one millimeter deep and having a diameter of less thanapproximately 0.5 mm, and thereby able to be measured at high precisiononly by using a target mark associated with the contact shape elementand emerging from the shaft of the probe extension above the contactshape element and entering the recess only slightly or not at all andthus able to be completely captured by the optical sensor, and therebyachieving improved lighting for the optical measuring of the deflectionof the target mark.

Previously known devices and methods have the problem that the targetmark appears at only low brightness in the optical sensor. Coating theside of the mark or target mark facing away from the sensor according tothe means of the prior art improves said problem, but based onexperience sufficient brightness cannot be ensured, particularly forlong probe pin or probe extension lengths and thus great distancesbetween the optical sensor and the target mark, because large portionsof the light entering the shaft run through the target mark and can exitthe probe element or probe extension through the uncoated shaft and theuncoated contact shape element. Said radiation exiting the probe elementor probe extension also cause interfering reflections under someconditions, due to light portions reflected or scattered at theworkpiece, and can falsify the measurement.

In order to achieve the object it is necessary to significantly increasethe portion of the light entering the probe element or probe extensionavailable for analysis.

At least some considerations of said object are substantially achievedby a device for determining geometric features and structures on aworkpiece by means of a tactile/optical sensor at least made of an atleast partially flexurally elastic probe extension, at least thefollowing emerging from the probe extension: a contact shape element fordeflecting when contacting the workpiece, and a target mark associatedwith the contact shape element for deflecting when the contact shapeelement contacts the workpiece such that the lateral deflection thereof,perpendicular to the optical axis of a laterally measuring opticalsensor can be captured by means of the optical sensor, preferably animage processing sensor, wherein the side of the target mark facing awayfrom the optical sensor at least partially has a reflecting orfluorescing layer, and wherein the region of the shaft of the probeextension running between the target mark and the contact shape elementis at least partially coated and/r the contact shape element is at leastpartially coated with a reflecting or fluorescing layer.

According to a refinement of this idea, the region of the shaft of theprobe extension running between the target mark and the contact shapeelement is entirely coated and the contact shape element is entirelycoated with a reflecting or fluorescing layer.

According to a particularly preferred solution according to theinvention, the layer is a metal layer and is preferably covered by ahard-surfaced or wear-resistance protective layer such as a siliconnitride layer at least in the region thereof making contact with theobject.

It is further characteristic that the target mark is spherical or nearlyspherical in design and is coated with the reflecting or fluorescinglayer on the area thereof facing away from the optical sensor up to orapproximately up to the equator.

According to an embodiment of the invention, the light emitted by thereflecting or fluorescing layer produces an image associated with thetarget mark, preferably a light spot arising due to bundling on theoptical sensor, such that the lateral deflection thereof can be capturedby the laterally measuring optical sensor.

In a further preferred embodiment according to the invention, a secondtarget mark emerges from the probe extension and can be captured bymeans of a second sensor, preferably a distance sensor.

The idea is particularly emphasized that the tactile/optical sensor isintegrated in a coordinate measuring machine, preferably a multisensorcoordinate measuring machine, together with additional sensors,preferably tactile, optical, or computed-tomography sensors.

The present invention relates to a method for determining geometricfeatures and structures on a workpiece by means of the device accordingto the invention.

The object of the invention is thus achieved by a method for determininggeometric features and structures on a workpiece by means of atactile/optical sensor at least made of an at least partially flexurallyelastic probe extension, at least the following emerging from the probeextension: a contact shape element for deflecting when contacting theworkpiece, and a target mark associated with the contact shape elementand deflecting when the contact shape element contacts the workpiecesuch that the lateral deflection thereof, perpendicular to the opticalaxis of a laterally measuring optical sensor having the optical sensor,preferably an image processing sensor, is captured, characterized inthat the beam emitted by at least one part of the reflecting orfluorescing layers is imaged on the laterally measuring optical sensorby means of a device according to at least one or the preceding claims,and that the lateral deflection of the contact shape element isdetermined from the image.

In a first preferred refined according to the invention, the secondtarget mark emerging from the probe extension is captured by the secondsensor, preferably a distance sensor, preferably in that the measurementbeam of the distance sensor is at least partially reflected at thesecond target mark.

The idea is particularly emphasized that the tactile/optical sensor isused in a coordinate measuring machine, preferably a multisensorcoordinate measuring machine, together with additional sensors,preferably tactile, optical, or computed-tomography sensors.

An independent invention relates to a method for automaticallydetermining geometric features and/or contours on workpieces by means ofa coordinate measuring machine.

The independent invention further relates to automatically opticallymeasuring geometric features and/or contours on workpieces by means ofan image processing sensor.

Features refer, for example, to diameters, distances, angles, surfaceparameters such as shape and roughness or the like of geometric elementssuch as lines or line segments, circles, segments of circles, surfaces,etc. Contours in particular refer to edges, typically shown as a stringof points on lines, circles, segments of circles, free-form lines, etc.Features such as contours are associated with actual dimensions byanalyzing the location of measured points. This is done, for example, byselecting the measurement points associated with a feature or a contour.Said selection is made, for example, by setting a measurement windowwithin a recorded image or overall images assembled from a plurality ofsingle images or automatically by means of a measurement program. Theimages can already be preprocessed, for example by means of filters, orbe present in a generalized representation comprising edges alreadydetected in the images, for example. Within the measurement window,already present measurement points are selected or measurement pointsare derived by means of suitable image processing methods, preferably atobject edges, steps, or the like.

In order to select the measurement window position to be associated witha particular feature according to the prior art, it is necessary toteach a corresponding measurement program, wherein the user detects thefeature using at least one recorded image and manually defines themeasurement window position. Alternatively, the definition can takeplace in advance using a CAD model of the workpiece, in that the CADmodel is imported into the measurement program. Automated measurementwithout user intervention is not possible, however, because theassociation of the measurement program with the previously selected CADmodel and the present workpiece must be made by the user for measuringthe particular workpiece, and the orientation of the workpiece, that is,the position and rotation as well as potentially mirroring on themeasurement bench must be derived by measuring selected features(so-called preliminary measurement) and a workpiece coordinate systemderived therefrom with respect to the CAD coordinate system, and thecoordinate systems must be adapted to each other so that the previouslydetermined measurement window can be placed at the correction locationon the workpiece, that is, the position of the particular feature.

Other methods exist wherein features, particularly regular geometricelements, are automatically detected in the image, as described inEP1319164, for example. A disadvantage thereby, however, is that no linkto specified data exists, for example in the form of a technical drawingsuch as a CAD drawing or an inspection plan, and often comprisingtolerances associated with the features. Said link and the alignment ofthe coordinate systems of the workpiece and the specified data arenecessary, however, in order to determine whether the specified datahave been met, optionally considering the tolerances, or how great thedeviation from the specified data or specified dimensions or specifiedgeometries of the features are. The fitting of measured data tospecified data is known under the terms best fit or Gaussian fit.Fitting considering the tolerances is described in EP1157313, to whichreference is made to the full extent.

The object of the present invention is to enable simple and rapidmeasuring, using as little user intervention as possible, for aplurality of features on a workpiece arbitrarily present from aplurality of known workpieces, wherein the result of the measurement isthe actual dimensions of the features and optionally also a statementabout compliance with or the degree of underrun or overrun with respectto the specified tolerances or the specified geometry.

The features or contours to be measured should preferably be detected bymeans of a specified geometry or plurality of specified geometries, suchas an inspection plan associated with a CAD model or a technical drawingor a similar computer-readable representation such as a file, whereinsaid file or an additional computer-readable representation such as afile comprises the tolerances associated with the features.

In order to achieve the object it is necessary to automatically selectthe specified data such as the CAD model and tolerance data associatedwith the particular present workpiece.

At least some considerations of the objects are achieved in that theselection of the specified data associated with the particular workpiecetakes place automatically, in that the image or overall image iscompared with previously determined images or overall images (templates)of the plurality of eligible workpieces, preferably by means ofcorrelation analysis, and the specified data associated with thepreviously determined image of the workpiece for which the greatestmatch is present are selected.

Automatically means that the least possible user intervention shouldtake place during the actual measuring of the workpiece. This means thatthe user simply places the workpiece on the measurement bench and themeasuring begins, wherein the placing and starting can also be done by afeeder system such as a robot. Starting a measurement means that anarbitrary means of input is actuated, such as a physical button or abutton in a computer program by means of a mouse click or the like.Alternatively, the measuring starts automatically when the measuringmachine detects the presence of a workpiece, for example due to theincreased mass of the measurement bench using a corresponding sensorsuch as a force sensor or using the change in continuously capturedimages of the optical sensor. Automatically further means that after themeasurement is started, no further user intervention is required untilthe results of the measurement are read, that is, the dimensions of thedetected features or deviations from the specified dimensions of thefeatures, that is, in particular no measurement windows must be set forselecting the features to be measured and for selecting the specifieddata associated with the workpiece. The reading of the measured valuescan also take place only after automatic further processing, such asautomatic export to a CAQ system or the like. Automatic measuring isfurther characterized in that a measurement program does not need to becreated in advance especially for the present workpiece. A previouslycreated measurement program, valid for all eligible workpieces, is thusstarted. A plurality of measurement programs can thereby optionallyexist, from which the user can make a selection, wherein the measurementprograms use different analysis strategies or detection algorithms, forexample, but can always be used independently of the present workpiece.As preparation for automatic measuring, however, it is necessary torecord and to save the specified data and all tolerances associated withthe specified data and previously determined images or overall images(tolerances) of workpieces such as master parts, in order to be able toaccess said records during the automatic measuring. The term automaticmeasuring used below refers, therefore, to the parts of the methodaccording to the invention between starting a measurement program afterplacing a workpiece on the measurement bench of a measuring machine andreading out the measurement results, wherein the measurement program isstarted without knowledge of the present workpiece or the orientationthereof.

The invention thus relates to a method for automatically determininggeometric features and/or contours of an eligible workpiece from aplurality of workpieces by means of an optical sensor, preferably animage processing sensor, one or more images of the workpiece beingrecorded and optionally merged into an overall image, features and/orcontours being extracted from the image or the overall image, a fitbeing performed between the extracted features and/or contours and thespecified geometries of the features and/or contours, the specifiedgeometries being taken from the specified data associated with theparticular workpiece and preferably the tolerances of the featuresand/or contours present in said specified data being provided for duringthe fit, and the actual dimensions and/or the deviations from thespecified geometries for the features and/or contours being madeavailable, wherein the selection of the specified data associated withthe particular workpiece takes place automatically, in that the image oroverall image is compared with previously determined images or overallimages (templates) of the plurality of eligible workpieces, preferablyby means of correlation analysis, and the specified data associated withthe previously determined image of the workpiece for which the greatestmatch is present are selected.

Specified data refers to all data describing the specified geometry of aworkpiece. Said data include, for example, drawing data from technicaldrawings or CAD data present in the form of a file, and can also bepresent in the form of inspection plans. Tolerances are typically alsoassociated with the features described by the specified geometry in thegeometry or dimensions thereof. Said tolerances are thus also includedin the specified data. Also included in the specified data are anyimages of master parts previously recorded according to the invention,that is, workpieces corresponding at least approximately to thespecified geometry of the particular workpiece. Said images are saved astemplates, for example, and are associated with the further specifieddata, particularly the tolerances, or vice versa, the tolerances areassociated with templates.

It is therefore emphasized that the specified data are drawing data suchas CAD data and are preferably the tolerances associated with thefeatures and/or contours present in the drawing data.

In a preferred refinement according to the invention, the tolerancesassociated with the specified geometries of the features and/or contoursare provided for when fitting individual features and/or contours or aplurality of or all of the features and/or contours, wherein the fit isperformed such that none of the tolerances are exceeded, whereinpreferably the minimum underrun of the tolerances is maximized, or thatif the tolerances are exceeded then the maximum overrun is minimized.

The corresponding requirements for maximum underrun or minimum overrunof the tolerance limits are fulfilled by optimization methods known tothe prior art. It is first differentiated whether a fit of all featuresand/or contours, particularly to the measurement points associatedtherewith, can be fully fit into the zones about the specified geometrydefined by the tolerances. If this is the case, then the fit is madesuch that the deviations from the tolerance limits, that is, the outeredges of the zones, are maximized, that is, the measurement points arefit so as to be as far from the tolerance limits as possible. Maximumunderrun thereby means that the distance of the point nearest thetolerance limits is as great as possible. Said maximum underrun is thetarget function of the optimization task, under the secondary conditionthat the measurement points must all further lie within the tolerancelimits. For ideally present measurement data, that is, correspondingprecisely to the specified data, the fit leads to the measurement dataand specified data being identical, that is, the deviation of the valuenearest the tolerance limits corresponds precisely to the value of thetolerance at said location. In the second case, it is not possible tofit all measurement points within the tolerance zones, that is, at leastone measurement point is outside of the tolerance zones. Said deviationshould be minimal. If said measurement points are outside of thetolerance limits, then the fit should occur such that the maximumdeviation from the tolerance limits is minimized by means of theoptimization task.

It is further characteristic that the deviations from the specifiedgeometries provided as a result of the fit comprise information aboutconformance to the tolerances and/or the maximum and/or minimum underrunand/or overrun of the tolerances and/or specified geometries.

In order to select the specified data matching the present workpieceaccording to the invention, it is necessary to compare the recordedimage or overall image with the templates of all previously measuredworkpieces or master parts and to find the greatest match. Correspondingcomparisons of the match can be performed according to the invention bydetermining the correlation. The information present in the images,namely the greyscale values in the case of a greyscale value image, orthe intensity values of the color channels in the case of a color image,are thereby compared and the deviations are determined. This isperformed for all templates and for different relative positions androtations and optimally mirroring of the specified or actual image inorder to detect the correct workpiece and the position and rotationthereof on the measurement bench, and optionally to determine whetherthe workpiece has been placed in opposite orientation or therepresentation is distorted or shown at a slightly incorrectmagnification. The greatest of the correlation coefficients determinedin the plurality of comparisons, that is, for which the greatest matchis present, and the corresponding associated specified data are used forfurther analysis. In the correlation analysis, the user can limitdegrees of freedom in advance in order to enable more rapid comparison.

The proposal is therefore particularly emphasized that the comparison ofthe image or overall image with the templates is performed by means ofcorrelation analysis, wherein a translation and/or rotation and/ormirroring and/or linear or non-linear scaling or distortion of the imageis implemented as a degree of freedom for the correlation, preferablysuch that the user can limit the degrees of freedom.

In order to produce the templates, for example, the invention proposesthat images of master parts of the corresponding workpieces are recordedand saved, and associated with the specified data of the correspondingworkpiece. In order to account for the fact that different lightsettings can be present for the actual measuring of the workpiece,templates are also preferably saved at various light settings.Alternatively, the templates can be synthesized from the CAD data.Synthetic images can be generated, for example, by using the location ofedges, raised areas, etc. from the specified data and optionally asimulated light impingement corresponding to the lighting of themeasuring machine, in order to compute a theoretical, synthetic image.Here again, various light settings can be used for generating aplurality of templates.

According to a particularly preferred solution according to theinvention, the templates are created in advance from one or moremeasurements of master parts of the plurality of workpieces or that thetemplates are synthetic images determined from the CAD data of theplurality of workpieces and preferably from the provision for the typeof light set for the measurement of the particular workpiece, such astransmitted light, darkfield incident light, or brightfield incidentlight, and the light intensity, and the templates are associated withthe specified data of the particular workpiece.

According to an embodiment of the invention, a plurality of templatesare created for each workpiece from the plurality of workpieces, whereinthe parameter of type of light, such as transmitted light, darkfieldincident light, or brightfield incident light and/or the light intensityare varied and the parameters set for measuring the particular workpieceare provided for in the comparison of the image or overall image withthe templates.

After the associated template and thereby the relevant workpiece and thelocation thereof have been identified by means of correlation analysis,the comparison of the specified and actual data, such as dimensions offeatures, should then take place. To this end, the features must beextracted from the recorded image or overall image. Because thespecified location of the features is known from the specified data,corresponding measurement windows can be set automatically in an imagealigned to the template and thus also to the drawing data.

It is therefore preferably provided that a first at least rough fit ofthe image or overall image of the workpiece to the template is performedusing the location of the particular workpiece determined by means ofthe correlation analysis, particularly the position, rotation, andmirroring.

The idea is particularly emphasized that only the parts of the image orthe overall image associated with the location of the features and/orcontours using the specified data are automatically provided for,preferably by automatically placing windows, for extracting the featuresand/or contours from the image or overall image, wherein the associationis made using the first at least rough fit.

According to an embodiment of the invention, a plurality of images ofsegments of the workpiece are recorded in different relative positionsbetween the sensor and the workpiece and are merged into an overallimage, wherein the relative positions determined by means of measurementaxes are preferably provided for when merging and preferably a uniformpixel raster is generated for the overall image by means of resampling.

Corresponding methods, for example, can be found in DE10341666 andDE102004058655, but also in DE10211760, to which reference is made infull.

In an independent solution according to the invention, the selection ofthe specified data associated with the particular workpiece is performedautomatically in that all features and/or contours are automaticallyextracted from the image or overall image and are fit into all specifiedgeometries of the plurality of eligible workpieces, and the specifieddata for which the greatest match is present during the fit areselected, particularly the least deviation from the specifiedgeometries.

Said solution of the object of the invention thus uses known methods forautomatically detecting features and/or contours from unknown images.Subsequently, rather than comparing the images themselves with thetemplates, the automatically detected features and contours are comparedwith the specified geometries known from the specified data. Said methodis significantly more subject to false associations, but is faster forsimple features.

The invention thus relates to a method for automatically determininggeometric features and/or contours of an eligible workpiece from aplurality of workpieces by means of an optical sensor, preferably animage processing sensor, one or more images of the workpiece beingrecorded and optionally merged into an overall image, features and/orcontours being extracted from the image or the overall image, a fitbeing performed between the extracted features and/or contours and thespecified geometries of the features and/or contours, the specifiedgeometries being taken from the specified data associated with theparticular workpiece and preferably the tolerances of the featuresand/or contours present in said specified data being provided for duringthe fit, and the actual dimensions and/or the deviations from thespecified geometries for the features and/or contours being madeavailable, wherein the selection of the specified data associated withthe particular workpiece is performed automatically in that all featuresand/or contours are automatically extracted from the image or overallimage and are fit into all specified geometries of the plurality ofeligible workpieces, and the specified data for which the greatest matchis present during the fit are selected, particularly the least deviationfrom the specified geometries.

The method according to the invention is further characterized in thatthe method is applied in a coordinate measuring machine, preferably amultisensor coordinate measuring machine, together with additionalsensors, preferably tactile, optical, tactile/optical, orcomputed-tomography sensors.

An independent invention relates to a device for dimensionally measuringgeometric features and contours on workpieces by means of a multisensorsystem made of at least one optical and one tactile sensor, wherein themultisensor system is preferably used in a coordinate measuring machine.

In order to address as great a number of measurement tasks as possible,different sensors are often combined in one machine, such as acoordinate measuring machine. Optical sensors are used thereby, forexample image processing sensors or optical distance sensors, tactilesensors such as measuring probes, or tactile/optical sensors such as aredescribed in EP0988505 or DE 10 2010 060 833. The sensors are typicallydisposed adjacent to each other, for example on one or more rams of acoordinate measuring machine. The sensors thereby have differentmeasurement locations or working points, that is, an offset (sensoroffset), and therefore measure in the corresponding measurement positionof the ram with respect to the workpiece at different points on theworkpiece or different locations in the measurement volume of acoordinate measuring machine. This is disadvantageous in that themeasurement range jointly usable by the sensors is limited and themeasurement range of the machines may possibly need to be larger indesign and therefore more expensive.

The sensor offset must be calibrated at a fixed point, for example themeasurement location of a reference sensor, prior to measuring by meansof the particular sensor, and must be considered when combining themeasurement results of different sensors in a coordinate system. Thegreater the offset, the greater the errors that occur due tomechanically or thermally induced strains or bends.

The object is therefore always to integrate a plurality of sensors witheach other so that said sensors measure at approximately the sameposition, that is, have common measurement locations or working points.It is further already advantageous if the measurement locations areidentical in at least two directions, preferably the horizontal, so thatonly the third, vertical axes of motion and measurement must becorrespondingly larger in design.

Corresponding integration of a plurality of sensors is known in theprior art for a plurality of optical sensors, for example a plurality ofzoom stages of a zoom optic or selectively usable laser distance sensorsintegrated in the optic using the Foucault principle (also known as TTLlasers—through-the-lens lasers) or for combining with a tactile/opticalsensor. A plurality of tactile sensors, particularly a plurality ofprobe inserts or measurement systems associated with the particularprobe system, can also be interchangeably disposed for determining theprobe deflection. Typically changeout interfaces are used, allowingautomated changeout by using the axes of the coordinate measuringmachine and placing in parking stations, or manual changeout by theoperator. Corresponding changeout interfaces have magnetic connections,for example, and provide, in addition to the mechanical coupling,releasable electrical or optical connections between the various sensorheads or probe inserts and the measuring machine.

Not known, however, is a corresponding combination of optical sensorsand conventional tactile sensors such as probes for coordinate measuringmachines, such as are produced by the Renishaw plc company, for example.

The object of the present invention is to provide a multisensor systemby means of which optical and tactile measurements can be performedusing interchangeable sensors, wherein the disadvantages of the priorart are to be avoided.

The object is achieved in that a multisensor system is designed so thata plurality of optical and tactile sensors can be disposed so as to havea nearly common measurement location or the measurement locations of thesensors nearly lie in a straight line defined by the imaging directionor optical axis of the optical sensor or sensors and passing through themeasurement location.

According to the invention, the various sensors can be integrated suchthat the measurement location at which the sensors record themeasurement data of the workpiece is identical or nearly identical foras many sensors as possible, but at least various measurement locationslie on a line in the imaging direction of the optical sensors or on theoptical axis.

In the context of the present invention, nearly identical or nearlycommon measurement locations is understood to mean that the locations atwhich the measurements are taken are identical or at least nearlyidentical, that is, only a few millimeters apart, preferably less than10 mm apart, particularly preferably no greater than one millimeterapart. In the case of planar measuring optical sensors, such as imageprocessing sensors, the measurement location is preferably the center ofthe planar measurement region, for example the center of the imagedsensor chip. For tactile sensors, the center of the probe element, forexample the center of the probe sphere, or the extreme point such as thepole of the probe sphere facing toward the workpiece, defines themeasurement location.

At least some considerations of said objects are thus substantiallyachieved by a multisensors system for measuring features and/or contourson a workpiece made of at least one optical and one tactile sensor,wherein at least some of the various sensor heads of the sensors can beinterchangeably disposed in that the sensors can be disposed so as tohave a nearly common measurement location, or the measurement locationsof the sensors nearly lie on a straight line defined by the imagingdirection or the optical axis of the optical sensor or sensors.

The idea is emphasized that the interchangeable sensor heads can bereleasably connected to the multisensor system by means of at least onechangeout interface, preferably a magnetic changeout interface,preferably automatically interchangeably by means of at least oneparking station.

In a first preferred refinement according to the invention, theinterchangeable sensor heads can be connected to the multisensor systemby means of a first changeout interface and a first parking station, orby means of a second changeout interface and a second parking stationprovided by one or more adapters for disposing on the first changeoutinterface and interchangeable by means of the first parking station,wherein the adapter is preferably a rotary or tilting or rotary/tiltingdevice.

By means of adapters it is particularly easily possible to connect thedifferent sensor heads of different tactile sensors. Examples of tactilesensors are the TP200 switching probe system and the SP25 measuringprobe systems from Renishaw plc. A probe system thereby typicallycomprises a permanently installed base element and an interchangeableprobe head comprising the measuring system and interchangeable probeinserts in turn. The probe inserts typically comprise a plate, the probepin, and the probe or contact element, or probe pin arrangements havinga plurality of contact elements such as star probes. The probe insertsare interchangeably attached to the measurement system by means of theplate. The second changeout interface present at the adapters allows themeasurement system, including the attached probe insert, that is, theprobe head, to be changed out. The adapter thus already comprises thebase element and the second changeout interface is thus copied from thealready present interfaces of the particular tactile sensor for changingout the measurement system. Alternatively, the measurement system canalso already be integrated in the adapter and the second changeoutinterface enables the probe insert to be changed out. The firstchangeout interface, in contrast, allows the particular adapter and thusthe entire probe system to be set aside, for example in order to changein a tactile/optical sensor or an auxiliary lens for a permanentlyintegrated optical sensor, or to measure solely by means of the opticalsensor.

It is therefore further characteristic that the interchangeable sensorheads comprise tactile or tactile/optical probe elements, particularlydifferent probe inserts and/or probe pines or probe pin arrangementssuch as star probes, wherein the sensor heads comprising differenttactile probe elements can preferably be interchangeably connected toone of the adapters by means of the second parking station and thesensor heads comprising different tactile/optical probe elements areinterchangeably disposed by means of the first changeout interface andby means of the first parking station.

The idea is particularly emphasized that a plurality of optical sensorsare formed by a zoom optic, preferably a zoom optic having a workingdistance adjustable independently of the imaging scale, and/or adistance sensor such as a focus sensor or Foucault sensor or chromaticsensor integrated in the optic, and/or an auxiliary lens for disposingat the first changeout interface.

According to a particularly preferred solution according to theinvention, an optical sensor comprising an optic is permanentlyintegrated in the multisensor system and the first changeout interfaceis disposed on the object side in front of and/or all around the optic.

According to an embodiment of the invention, therefore, the multisensorsystem comprises brightfield illumination integrated in the optic and/ordarkfield illumination disposed all around the optic.

It is preferably provided that the multisensor system and/or the one ormore parking stations are integrated in a coordinate measuring machine,preferably in a multisensor coordinate measuring machine, together withadditional sensors, such as tactile, optical, tactile/optical, orcomputed-tomography sensors.

It is further characteristic that a controller is associated with themultisensor system and preferably with the coordinate measuring machineand provides the calibrated sensor offset for the analysis automaticallyand independently of the sensor used, preferably in a common coordinatesystem.

An independent invention relates to a device and a method fortactile/optical measuring of geometric features and structures on aworkpiece.

An independent invention further relates to interferometricallydetermining the vertical deflection of a contact shape element or a markassociated therewith emerging from a flexurally elastic probe extension.

Tactile/optical sensors are described in the following specifications ofthe applicant.

EP0988505 describes a method and a device wherein a probe element (firsttarget mark) and optionally a further target mark emerge from a probeextension via a flexurally elastic shaft, the coordinates thereof whendeflected being determined by means of an optical sensor.

A similar sensor is described in EP 1 071 921, wherein the contact forceis adjusted by means of the rigidity of the flexurally elastic shaft, inthat solely the bending length 1 is varied.

An opto-mechanical interface having an adjusting device for acorresponding sensor is described in EP 1 082 581.

DE 198 24 107 describes the use of a corresponding sensor for a surfaceprofiling method.

A corresponding sensor is operated on a rotating or pivoting joint in DE10 2004 022 314.

PCT/EP01/10826 describes coating a probe element or probe extension onthe side facing away from the sensor in order to generate a luminousmark in the interior of the probe element by bundling the radiationreflected at the coating, said radiation being introduced into theinterior of the shaft of the probe element or probe extension, thelength thereof being measured, and a mark associated with the probeelement and formed by a darkened region of the luminous shaft of theprobe element.

DE 10 2010 060 833 describes a tactile/optical sensor wherein, inaddition to determining the position of a contact shape element or atleast a target mark associated therewith in the X and/or Y direction ofthe coordinate measuring machine using a first sensor such as an imageprocessing sensor, a second sensor such as a distance sensor alsodetermines the Z-direction, wherein at least one flexible connectingelement is used for mounting the contact shape element and the targetmark in a mounting element, said connecting element being penetrated bythe beam path of the first sensor in the beam direction, wherein the atleast one flexible connecting element is transparent and/or is severelydefocused with respect to the first sensor. The distance sensorcapturing the deflection in the Z direction (vertical direction) of thecontact shape element or at least a target mark associated therewith isproposed to be an interferometer, particularly an absolutely measuringheterodyne interferometer. In a preferred solution, the measurement beamof the interferometer is thereby coupled into the flexurally elasticprobe extension (fiber). Details on beam guiding, particularly for thereference beam path, are not explained. DE 10 2010 060 833 furtherproposes that the measurement beam of a distance sensor is reflected ata mark mounted on the sensor-side end of the flexurally elasticextension. The disadvantage occurs thereby that due to the bending ofthe fiber only one component of the vertical deflection is captured, butnot the entire deflection, thus limiting the sensitivity. Theassociation between the deflection of the contact shape element and thecaptured measured value of the distance sensor must therefore becalibrated. Measurement deviations thereby occur due to the potentiallydirectionally dependent behavior of said association, wherein saidbehavior cannot be fully captured during calibration.

In a further solution, for example as disclosed in Andreas Ettemeyer:“New three-dimensional fiber probe for multisensor coordinatemeasurement”, Opt. Eng. 51(8), 081502 (May 14, 2012);http://dx.doi.org/10.1117/1.OE.51.8.081502, direct interferometricmeasuring of the contact shape element is proposed in order to improvesensitivity. The measurement beam (laser light) coupled into the fiberis thereby output from the fiber by the contact shape element and issuperimposed on the reference beam (and made to interfere) and theinterference pattern thus produced (speckle) is analyzed. Two beamsources of different wavelength spectrum, particularly laser diodeshaving peak wavelengths of 635 nm and 675 nm, are preferably used inorder to achieve an absolute measurement of the deflection or positionof the captured contact shape element or the captured target mark. Inthe preferred solution shown for the construction of the optical beampath of the interferometric sensor coupled to the beam path of the imageprocessing sensor used for determining the lateral deflection (X and Ydirections), it is disadvantageous that the amount of light available isvery low due to the total of four optical splitters. Particularly thesplitter disposed directly ahead of the coupling of the measurement beamis passed through twice. The optical imaging of the image processingsensor further passes through said optical splitter and the amount oflight thereof is thereby reduced. It is further disadvantageous that thesuperposition of the measurement and reference beams does not take placeuntil after an imaging optic. Because only the measurement beam passesthrough the imaging optic, but the reference beam does not, differentbeam geometries are present and the interference produced is disturbedor at least not optimal. A complex and fixed construction also resultsfor the beam guiding of the reference beam. Said construction requires agreat deal of space and is further subject to drift effects, for exampledue to changes in temperature. It must be noted that the optical pathlength for the reference beam prior to the superposition with themeasurement beam must correspond to the optical path length of themeasurement beam, except for the coherence length of the beam used, inorder to produce interferences. In order that particularly long probeextensions of greater than 20 mm, for example, or even greater than 100mm in length can be used, for example in order to measure poorlyaccessible regions of the workpiece, correspondingly large optical pathlengths must also be provided for the reference beam. A disadvantage ofthe fixed construction of the reference beam path is further that saidpath cannot be adapted to probe extensions having different lengths.

Full reference is made to the disclosed contents of all previously namedspecifications of the applicant and to the publication named above.

The fundamental object of the present invention is to avoid thedisadvantages of the prior art or at least to reduce the effectsthereof.

One object of the present invention is therefore to disclose an improvedarrangement for directly interferometrically capturing the verticaldeflection of a contact shape element emerging from a flexurally elasticextension, particularly enabling compact construction, even for largeprobe extensions of varying lengths, wherein drift effects due to beamguiding of the measurement and reference beams are reduced and whereinthe amount of light available for analysis for the interferometricsensor (vertical Z direction) and for the image processing sensor(lateral X and Y direction) is increased.

A further object of the invention is to disclose a method by means ofwhich a more precise measurement is made possible, even for large orvariable lengths of the probe extension, particularly directlydetermining the vertical deflection of the contact shape element andoptionally also determining the bending of the contact shape element.Further parameters such as the contact force or the direction of thecontact force can be determined more precisely from the latter.

According to a first solution achieving at least part of the objectaccording to the invention, a compact construction is achieved in thatthe optical splitting of the beam of the interferometric sensor into ameasurement beam and a reference beam is performed by an opticalsplitting layer, for example a pellicle, that is, a film or mirror layerpartially transparent and partially reflective on both sides, disposeddirectly above the side of the probe extension facing away from theworkpiece, that is, on the probe extension side on the side further awayfrom or facing away from the contact element. Said splitting layer isalso used for deflecting the reference beam reflected back by areference mirror on the side of the probe extension facing away from theworkpiece into the optical axis or parallel or at an angle to said axis,that is, in the direction of the analysis unit, such as a camera, of thedistance sensor. The advantage thereof in comparison with the prior isthat the number of splitting layers has been reduced. The amount oflight for the distance sensor and for the optically laterally measuringsensor is thereby increased.

It can further be provided that particularly the dimensions transverseto the optical axis of the optically laterally measuring sensor used arekept small, in that the reference beam is deflected, for example in thedirection of the optical axis or at an angle thereto, optionallydeflected a plurality of times (folded). The corresponding deflectingmeans, such as a mirror, together with the reference mirror form thereference beam path. This is particularly advantageous if large lengthsare to be achieved for the probe extension, whereby correspondingly longoptical paths are require for the reference beam path.

At least some considerations of the objects are thus substantiallyachieved by a device for determining geometric features and structureson a workpiece, said device comprising at least a laterally measuringoptical sensor, preferably an image processing sensor, a verticallymeasuring interferometric distance sensor, and an at least partiallyflexurally elastic probe extension, at least the following emerging fromthe probe extension: a contact shape element for deflecting togetherwith the probe extension when contacting the workpiece and preferably atarget mark associated with the contact shape element for deflectingtogether with the probe extension when the contact shape elementcontacts the workpiece, wherein the lateral deflection of the contactshape element or the target mark perpendicular to the optical axis ofthe laterally measuring optical sensor can be determined by means ofsaid sensor and the vertical deflection along or nearly along theoptical axis of the laterally measuring optical sensor can be determinedby means of the distance sensor, wherein the measurement beam of theinterferometric distance sensor can be coupled into the probe extensionand emitted by the contact shape element or the associated target markand can be superimposed on the reference beam of the interferometricdistance sensor and the interferences (speckle) thus produced can beanalyzed, and wherein the device is characterized in that an opticalsplitting layer is disposed on the probe extension side on the far sidewith respect to the contact shape element and is penetrated by theoptical axis of the laterally measuring optical sensor, particularlyspaced apart from the probe extension, such that the optical splittinglayer is implemented for splitting the measurement beam and referencebeam, such that the splitting layer deflects the reference beamreflected by a reference mirror in a direction

-   -   parallel to, or    -   at an angle to, or    -   along the optical axis of the laterally measuring sensor with        respect to the side facing away from the contact shape element,        wherein one or more reflectors are disposed optionally between        the splitting layer and the reference mirror and together with        the reference mirror form a reference beam path, wherein the        reference beam can preferably be deflected into a direction        parallel to the optical axis or into a direction at an angle to        the optical axis of the laterally measuring sensor.

According to a second alternative solution, at least part of the objectis achieved according to the invention in that a compact construction isachieved in that the optical splitting of the beam of theinterferometric sensor into a measurement beam and a reference beam isperformed by an optical splitting layer also disposed directly above theside of the probe extension facing away from the workpiece, that is, onthe probe extension side on the side further away from or facing awayfrom the workpiece with respect to the contact element, but is disposedlaterally spaced far enough apart from the optical axis of the opticallylaterally measuring sensor so as to be outside of the beam path of theoptically laterally measuring sensor. The splitting thus occurs prior toentry into the aperture of the image processing sensor, and the beampath thereof is thereby not split by the splitting layer, therebyincreasing the amount of light available. Splitting outside of theoptical axis does necessarily mean, however, that the measurement beamstill must be deflected once more in the direction of the probeextension in order to be coupled into the probe extension on the sidefacing away from the workpiece. To this end, a deflecting device isprovided comprising a surface implemented as a reflector such as amirror. A second surface is preferably present on said deflecting deviceand brings about the deflecting of the reference beam in the directionof the analysis unit such as a camera of the distance sensor after saidbeam has travelled the reference beam path. The analysis unit ispreferably present on the side of the probe extension facing away fromthe workpiece, particularly in the direction of the optical axis orparallel to the direction of the optical axis or at an angle to thedirection of the optical axis. A corresponding deflection generally isperformed by at least two reflectors. A first reflector is necessary inorder to deflect the reference beam running after splitting at thesplitting layer along a path in the direction of the optical axisadjusted to correspond to the length of the probe extension. The secondor last reflector brings about the deflection in the direction of theanalysis unit. Depending on the length of the probe extension, as isalso the case for the first solution according to the invention, furtherreflectors can be disposed in the reference beam path in order to foldthe same, that is, to achieve large path distances in a small space.This is advantageous primarily if probe extensions having differentlengths are to be interchangeable in design together with the referencearm. The reflectors in the reference beam can thereby be disposed inmany potential variants so that the reference beam runs in one or moredirections parallel to the optical axis or at an angle to the opticalaxis. The reflectors, other than the last one, are thereby disposedlaterally adjacent to the optical beam path of the optically laterallymeasuring sensor in order to avoid disturbing said beam path.

At least some considerations of the objects are thus also substantiallyachieved by a device for determining geometric features and structureson a workpiece, said device comprising at least a laterally measuringoptical sensor, preferably an image processing sensor, a verticallymeasuring interferometric distance sensor, and an at least partiallyflexurally elastic probe extension, at least the following emerging fromthe probe extension: a contact shape element for deflecting togetherwith the probe extension when contacting the workpiece and preferably atarget mark associated with the contact shape element for deflectingtogether with the probe extension when the contact shape elementcontacts the workpiece, wherein the lateral deflection of the contactshape element or the target mark perpendicular to the optical axis ofthe laterally measuring optical sensor can be determined by means ofsaid sensor and the vertical deflection along or nearly along theoptical axis of the laterally measuring optical sensor can be determinedby means of the distance sensor, wherein the measurement beam of theinterferometric distance sensor can be coupled into the probe extensionand emitted by the contact shape element or the associated target markand can be superimposed on the reference beam of the interferometricdistance sensor and the interferences (speckle) thus produced can beanalyzed, and wherein the device is characterized in that an opticalsplitting layer is disposed on the probe extension side on the sidefacing away from the contact shape element and adjacent to the beam pathof the laterally measuring optical sensor, that the splitting layer isimplemented for splitting the measurement beam and reference beam, thatthe measurement beam can be deflected in the direction of the probeextension after passing through the splitting layer by means of areflector present on a first surface of a deflecting device, and thatthe reference beam can be deflected by means of at least two reflectorsfor forming at least part of the reference beam path in a direction thatis

-   -   parallel to, or    -   at an angle to, or    -   along the optical axis of the laterally measuring sensor with        respect to the side facing away from the contact shape element,        wherein the last acting reflector is preferably provided on a        second surface of the deflecting device, and wherein the        reference beam preferably runs between the at least two        reflectors in one or more directions parallel to the optical        axis or at an angle to the optical axis of the laterally        measuring sensor.

According to a further embodiment of the invention, the plurality ofreflectors are disposed adjacent to each other or laterally adjacent tothe optical beam path of the optically laterally measuring sensor fordeflecting the reference beam, with the exception of the last actingreflector or the splitting layer.

As a refinement of this idea, a device is provided wherein a target markimplemented as a reflector is mounted on the side of the probe extensionfacing away from the contact shape element and the vertical deflectionof the target mark can be captured by means of the beam path of afurther distance sensor such as a Foucault laser sensor or focal sensor,preferably in that the last acting reflector or splitting layer isimplemented such that less than the entire aperture of the beam path ofthe further distance sensor is covered.

The measurement beam associated with the further distance sensor therebyruns laterally about the splitting layer or laterally about thedeflecting device comprising the reflector passed through last, and istherefore not completely shadowed. By means of said construction it isadditionally possible to measure the deflection of the contact shapeelement indirectly. The comparison with the deflection measured by theinterferometric sensor can be used for evaluating the bending of theprobe extension and optionally the contact force, or for calibrating thefurther distance sensor.

According to a particularly preferred solution according to theinvention, the interferometric distance sensor comprises one or morebeam sources and the beam thereof is coupled in the direction of theoptical splitting layer perpendicular to or nearly perpendicular to theoptical beam path, wherein the guiding of the beam between the beamsource and the coupling point preferably occurs by means of opticalfibers.

The beam sources can thereby be constructed spaced apart, whereinoptical fibers or optical waveguides are preferably used, or near theoptical splitter and forming a unit at least with the same, said unitbeing interchangeable, for example. In the second case, only the signalsfor electrically actuating must be transmitted into the unit fromoutside.

It is further characteristic that the interferometric distance sensorcomprises two beam sources having different wavelength spectra, whereinthe beam sources are preferably laser diodes.

The absolutely measuring heterodyne methods known from the prior art canthereby be applied.

According to a further preferred embodiment of the invention, at leastthe one reflector, the splitting layer, the probe extension, andoptionally the reference mirror form a unit or are disposed in a devicesuch as a housing or mounting element for forming a unit, said unitbeing manually and/or automatically interchangeable by means of achangeout interface, preferably a magnetic changeout interface,connected directly or indirectly to the laterally measuring opticalsensor, preferably to an optic associated with the laterally measuringoptical sensor, wherein the changeout interface preferably furthercomprises a coupling location for guiding in the beam of theinterferometric distance sensor, or a coupling location for electricallyactuating the one or more beam sources of the interferometric distancesensor integrated in the unit.

It is thereby made possible using particularly simple means to usedifferent probe extensions, particularly probe extensions havingdifferent lengths, in a preferably automatic measurement sequence. Eachunit thereby comprises a reference beam path adapted to the particularprobe extension and thus changed out with said unit. Units not in useare placed in known changeout stations for coordinate measuringmachines, for example.

The idea is particularly emphasized that the tactile/optical sensor isintegrated in a coordinate measuring machine, preferably a multisensorcoordinate measuring machine, together with additional sensors,preferably tactile, optical, or computed-tomography sensors.

The present invention further relates to a method for determininggeometric features and structures on a workpiece, preferably by means ofthe device according to the invention.

The object of the invention is thus achieved by means of a method fordetermining geometric features and structures on a workpiece by means ofa tactile/optical sensor comprising at least a laterally measuringoptical sensor, preferably an image processing sensor, a verticallymeasuring interferometric distance sensor, and an at least partiallyflexurally elastic probe extension, at least the following emerging fromthe probe extension: a contact shape element deflecting together withthe probe extension when contacting the workpiece, and preferably atarget mark associated with the contact shape element and deflectingwhen the contact shape element contacts the workpiece, the lateraldeflection of the contact shape element or of the target markperpendicular to the optical axis of the laterally measuring opticalsensor being captured by means of the same, and such that the verticaldeflection of the contact shape element or of the target mark along theoptical axis of the laterally measuring optical sensor can be capturedby means of the distance sensor, the measurement beam of theinterferometric distance sensor being coupled into the probe extensionand being emitted by the contact shape element or the associated targetmark and superimposed with the reference beam of the interferometricdistance sensor, and the interferences (speckle) arising thereby beinganalyzed, characterized in that an optical splitting layer is disposedon the probe extension side on the far side with respect to the contactshape element and is penetrated by the optical axis of the laterallymeasuring optical sensor, particularly spaced apart from the probeextension, such that the optical splitting layer is implemented forsplitting the measurement beam and reference beam, such that thereference beam reflected by a reference mirror is deflected by thesplitting layer in a direction

-   -   parallel to, or    -   at an angle to, or    -   along the optical axis of the laterally measuring sensor with        respect to the side facing away from the contact shape element,        wherein optionally one or more deflections of the reference beam        path occur between the splitting layer and the reference mirror        by means of one or more reflectors forming a reference beam path        together with the reference mirror, wherein preferably the        reference beam is deflected preferably in a direction parallel        to the optical axis or in a direction at an angle to the optical        axis of the laterally measuring sensor.

At least some of the objects of the invention are thus achieved by meansof an alternative method for determining geometric features andstructures on a workpiece by means of a tactile/optical sensorcomprising at least a laterally measuring optical sensor, preferably animage processing sensor, a vertically measuring interferometric distancesensor, and an at least partially flexurally elastic probe extension, atleast the following emerging from the probe extension: a contact shapeelement deflecting together with the probe extension when contacting theworkpiece, and preferably a target mark associated with the contactshape element and deflecting when the contact shape element contacts theworkpiece, the lateral deflection of the contact shape element or of thetarget mark perpendicular to the optical axis of the laterally measuringoptical sensor being captured by means of the same, and such that thevertical deflection of the contact shape element or of the target markalong the optical axis of the laterally measuring optical sensor can becaptured by means of the distance sensor, the measurement beam of theinterferometric distance sensor being coupled into the probe extensionand being emitted by the contact shape element or the associated targetmark and superimposed with the reference beam of the interferometricdistance sensor, and the interferences (speckle) arising thereby beinganalyzed, wherein an optical splitting layer is disposed on the probeextension side on the far side with respect to the contact shape elementand adjacent to the beam path of the laterally measuring optical sensor,such that the optical splitting layer is implemented for splitting themeasurement beam and reference beam, such that the measurement beam isdeflected in the direction of the probe extension by means of areflector present on a first area of a deflecting device after passingthrough the splitting layer, and that the reference beam is deflected bymeans of at least two reflectors for forming at least one part of thereference beam path in a direction

-   -   parallel to, or    -   at an angle to, or    -   along the optical axis of the laterally measuring sensor with        respect to the side facing away from the contact shape element,        wherein a second area of the deflecting device is preferably        used as the last acting reflector, and wherein the reference        beam runs between the at least two reflectors in one or more        directions parallel to the optical axis or at an angle to the        optical axis of the laterally measuring sensor.

According to a preferred refinement of the invention, the verticaldeflection of a side of a target mark additionally implemented as areflector mounted on a side of the probe extension facing away from thecontact shape element is captured by means of the beam path of a furtherdistance sensor, such as a Foucault laser sensor or focus sensor, andthe flexion of the probe extension and/or the magnitude and/or thedirection of the contact force is preferably determined from themeasured values of the interferometric distance sensor and the measuredvalues of the further distance sensor, wherein an area is preferablyused as the reflector passed through last or as the splitting layer andis implemented such that less than the entire aperture of the beam pathof the further distance sensor is covered.

According to a particularly preferred solution according to theinvention, the reference beam is deflected by means of a plurality ofreflectors, wherein, except for the reflector passed through last or thesplitting layer, the reflectors are disposed adjacent to each other orlaterally adjacent to the optical beam path of the optically laterallymeasuring sensor.

According to an embodiment of the invention, therefore, the beam of theone or more beam sources of the interferometric distance sensor iscoupled in the direction of the optical splitting layer perpendicular toor nearly perpendicular to the optical beam path, wherein the guiding ofthe beam between the beam source and the coupling point preferablyoccurs by means of optical fibers.

It is preferably provided that two beam sources having differentwavelength spectra, preferably laser diodes, are used for theinterferometric distance sensor, and absolute values are preferablydetermined for the deflection or position of the captured contact shapeelement or the captured target mark.

It is further characteristic that different units, each made of thereflectors forming the reference beam, the splitting layer, and theprobe extension, and optionally the reference mirror, are changed outmanually and/or automatically by means of a changeout interface,preferably a magnetic changeout interface, wherein the different unitseach comprise a different probe extension, particularly a probeextension having a different length, and a correspondingly adaptedreference beam path, particularly a reference beam path having adifferent length, and preferably correspondingly adapted positionsand/or quantity of reflectors.

The idea is particularly emphasized that the tactile/optical sensor isused in a coordinate measuring machine, preferably a multisensorcoordinate measuring machine, together with additional sensors,preferably tactile, optical, or computed-tomography sensors.

An independent invention relates to a method for non-contactingmeasuring of geometric features and contours on workpieces by means ofat least one optical and/or at least one computed tomography sensor in acoordinate measuring machine.

In particular, the invention relates to merging a plurality of images ofa workpiece recorded by means of an optical sensor such as an imageprocessing sensor, for example by means of a camera.

Recording a plurality of images of a workpiece or a region by means ofan optical sensor such as an image processing sensor and merging saidplurality of recorded individual images into an overall image, saidoverall image then being analyzed, is described for example inDE10341666. Resampling methods are also used, for example, as describedin DE 102004058655, in order to generate a uniform pixel raster for themerged overall image. Reference is made in full to the contents of bothspecifications. In both of said specifications of the applicant, asolution for precisely merging the individual images is disclosedwherein the location of the individual images relative to each other isdetermined in that the positions of the drives for implementing therelative motion between the workpiece and sensor are determined by meansof scales. Corresponding scale systems are expensive and the effortrequired for receiving and processing the scale signals is high.

An alternative solution for merging individual images into an overallimage is known to the person skilled in the art as stitching. The factthat overlapping recorded individual images comprise the same imageregions of the workpiece is thereby utilized. Said regions areassociated by means of correlation determination. A prerequisite for agood correlation, however, is that sufficient structures are present inthe overlapping regions. Said method is therefore disadvantageous inthat no merging can take place unless sufficient contrast and easilyassociated structures are present in the particular overlapping regions,so that the imaged workpiece is correspondingly structured. This cannotalways be ensured, however, such as for homogenous or reflectiveworkpiece surfaces.

An object of the present invention is to enable simple and rapid mergingof individual images of a workpiece having any arbitrary surface into anoverall image without using scale systems for determining the locationof the individual images relative to each other.

Said object is achieved in that a reference such as structures ismounted on the measurement bench on which the workpiece is placed or ona mounting element receiving the workpiece, for example, said referencebeing at least partially captured when recording the individual imagesof the workpiece. The location of said reference or structures in theindividual images is used for determining the location of the individualimages relative to each other, whereby precise merging of the individualimages is made possible.

At least some considerations of said objects are substantially achievedin that the location of the individual images to each other isdetermined in that structures mounted on the measurement bench arecaptured in the individual images and the location of the structures isdetermined.

The invention thus relates to a method for measuring geometric featuresand/or contours on a workpiece disposed on a measuring table by means ofan optical sensor, preferably an image processing sensor, wherein aplurality of single images of the workpiece or of a region of theworkpiece are recorded at different relative positions between theworkpiece and the sensor and are merged into an overall image, whereinthe location of the single images to each other corresponding to therelative positions are provided for when merging, and the featuresand/or contours are extracted from the overall image, wherein thelocation of the individual images to each other is determined in thatstructures mounted on the measurement bench are captured in theindividual images and the location of the structures is determined.

In order that at least part of the structure can be captured in allindividual images, regardless of the size and shape of the workpiece,the structures are preferably mounted in the edge region of themeasurement bench not covered by the workpiece. The distribution of theindividual images is thereby limited, such that each individual imagemust capture at least part of the edge region of the measurement bench.In at least one direction, therefore, only a maximum of two adjacentindividual images can be recorded, wherein any arbitrary number ofindividual images can be recorded in the direction perpendicularthereto.

The idea is therefore emphasized that the structures in the edge regionof the measuring table are captured and a maximum of two single picturesare recorded adjacent to each other in a first direction and anarbitrary number of single pictures are recorded in a second directionperpendicular to the first direction.

Said conditions are intended to ensure that a region of the structuresor reference is captured in each image.

The images themselves are recorded in a plane.

The individual two-dimensional images are recorded in transmitted lightand/or incident light.

Two potential interpretations can be understood for the location of thestructure in the context of the invention. In a first variant, theposition of a part of the structure, namely the part of the structurecaptured in an individual image in each case is understood with respectto an absolute location of the overall structure or structures. To thisend, the overall structure is fully captured and saved in advance. Thiscan be done, for example, by means of an image processing sensorpreferably recording a plurality of individual images of the measurementbench, particularly of the structures. The positions taken by the imageprocessing sensor when recording are thereby determined, for example inthat the image processing sensor is integrated in a coordinate measuringmachine having measurement axes, in order to compose a precise overallimage. The measurement bench is thereby measured by means of a differentcoordinate measuring machine, for example, prior to being installed in acoordinate measuring machine according to the present invention. Thelocation of each part of the structure in a coordinate system is therebyknown and thus the location of different parts relative to each other isalso known. For the actual measurement, a particular part of thestructure is recorded in each case. Said part must be detected again inthe previously recorded overall image. This is done by means ofcorrelation methods, for example. It must thereby be noted that therough position of the structure on the measurement bench, that is, therough position of the individual image in each case, is typicallyalready known, so that the correlation must be examined in only a partof the prior image. Otherwise the structures must be unique patterns andnot be repeated.

In a second variant, the position of a part of the structure, namely thepart of the structure captured in each individual image, is understoodsimply with respect to the part of the structure present in the adjacentrecorded individual images. To this end, it is necessary that adjacentindividual images overlap each other, whereby parts of the structure arealso uniformly present in adjacent individual images. By means ofcorrelation, the identical parts of the structure can be detected andthe relative location of the adjacent individual images can bedetermined therefrom.

According to a first preferred refinement of the invention, the locationof the structures on the measuring table is determined prior tomeasuring the workpiece, for example by recording a plurality of imagesby means of an image processing sensor, the positions thereof beingdetermined when recording the images, and that the current locationrelative to the location of the structures determined beforehand isdetermined by means of a correlation method when measuring theworkpiece.

According to a second preferred refinement of the invention, adjacentsingle images at least partially overlap each other and the location ofthe structures in the single pictures relative to each other isdetermined by means of a correlation method.

It is further characteristic that the structures are patterns such asbars or other geometric shapes, preferably non-repeating patterns,disposed at least in the edge regions of the measuring table, preferablyalong the entire edge region of the measuring table.

A corresponding device is further provided for implementing the methodaccording to the invention.

The invention thus further relates to a device for measuring geometricfeatures and/or contours on a workpiece, at least comprising a measuringtable on which the workpiece can be disposed and an optical sensor,preferably an image processing sensor, and means for relativedisplacement between the workpiece and the sensor, for recording andsaving a plurality of single images of the workpiece or a region of theworkpiece, merging into an overall image, and analyzing the overallimage, and means for extracting features and/or contours from theoverall image.

At least some considerations of the object of the invention are achievedin that structures, particularly patterns such as bars or othergeometric shapes, preferably non-repeating patterns, are disposed on themeasuring table at least in the edge regions of the measuring table,preferably along the entire edge region of the measuring table, and thatthe patterns can be captured by means of the optical sensor.

The method according to the invention and the device according to theinvention are further characterized in that use or integration in acoordinate measuring machine takes place, preferably a multisensorcoordinate measuring machine, together with additional sensors,preferably tactile, optical, tactile/optical, or computed-tomographysensors.

Further details, advantages, and features of the invention arise notonly from the claims, the features to be found therein—as such and/or incombination—but also from the following description of the drawings.

Shown are:

FIG. 1 A principal view of a device according to the invention in afirst embodiment having a first probe extension according to theinvention,

FIG. 2 A principal view of a device according to the invention in asecond embodiment having a second probe extension according to theinvention,

FIG. 3 A principle view of a device according to the invention in athird embodiment having a vertically measuring optical distance sensor,

FIG. 4a, b Principle views of alternative probe extensions according tothe invention,

FIG. 5a, b Principle views of a probe extension according to theinvention according to an independent idea,

FIG. 6 A principle view of a device according to the invention in afirst embodiment having a first laterally measuring optical sensor,

FIG. 7a A principle view of a device according to the invention in asecond embodiment having a first laterally measuring optical sensor anda second optical distance sensor in a first and particularly preferredembodiment of the probe extension,

FIG. 7b A principle view of a device according to the invention in thesecond embodiment having a first laterally measuring optical sensor anda second optical distance sensor in a second embodiment of the probeextension,

FIG. 7c A principle view of a device according to the invention in thesecond embodiment having a first laterally measuring optical sensor anda second optical distance sensor in a third embodiment of the probeextension,

FIG. 7d A principle view of a device according to the invention in thesecond embodiment having a first laterally measuring optical sensor anda second optical distance sensor in a first particular embodiment of theprobe extension in an L shape,

FIG. 7e A principle view of a device according to the invention in thesecond embodiment having a first laterally measuring optical sensor anda second optical distance sensor in a second particular embodiment ofthe probe extension as a star probe, and

FIG. 8 A principle view of a coordinate measuring machine comprising thearrangement according to the invention,

FIG. 9 A principle view of a device according to the invention in afirst embodiment having a first sensor, being a laterally measuringoptical sensor,

FIG. 10 A principle view of a device according to the invention in asecond embodiment having the first sensor, being a laterally measuringoptical sensor, and a second sensor, being a distance sensor,

FIG. 11 A flow diagram of a preferred embodiment of the method accordingto the invention,

FIG. 12 A preferred embodiment of the device according to the inventionhaving a changed-in tactile sensor head,

FIG. 13 A preferred embodiment of the device according to the inventionhaving a changed-in tactile/optical sensor head,

FIG. 14 A preferred embodiment of the device according to the inventionhaving a changed-in auxiliary lens,

FIG. 15 A principle view of a device according to the invention in afirst embodiment,

FIG. 16 A principle view of a device according to the invention in asecond embodiment, and

FIG. 17 A preferred embodiment of structures on a measurement benchcorresponding to the device according to the invention.

Various embodiments of one of the teachings according to the inventioncan be seen in the figures, wherein the same reference numerals arefundamentally used for the same elements in FIG. 1 through 5 b.

FIG. 1 shows a first embodiment of an arrangement according to theinvention for determining geometric features and structures of aworkpiece 27 having a tactile/optical sensor 1. Said sensor is made of alaterally measuring optical sensor, here an image processing sensor 2, aprobe extension 13, a fiber receptacle 14, adjusting means 18, a holder25, and two changeout interfaces 16 and 24.

The image processing sensor 2 is made of a camera 3 and an optic havinglenses 4 and 5, wherein the optic comprises the optical axis 26 and atarget mark 7 of the probe extension 13 is captured by means of the beampath 6.

The probe extension 13 comprises a flexurally elastic part or segment 10from which the target mark 7 emerges. Said segment is preferablyimplemented having a continuously tapering diameter, particularlypreferably conical, by means of a drawing process. The drawings alsoprovide clarification in principle.

A flexurally rigid part or segment 9 to which the contact shape element8 is attached emerges from the target mark 7 and is deflected whencontacting the workpiece 27 to be measured. Alternatively, the contactshape element 8 emerges directly from the flexurally elastic part 10 andthe deflection of the contact shape element 8 is captured by the beampath 6 and determined by the image processing sensor 2. The probeextension 13 is further connected to the fiber receptacle 14.

Flexurally rigid segments or parts 11, 12 are further connected to theflexurally elastic part 10, comprising a 90° bend in the region of thepart or segment 11 in the 2D sensor design shown here and running intothe fiber receptacle 14 at approximately a right angle to the opticalaxis 26 in the region of the part 12. A more flexurally rigid and thuspractically also flexurally rigid segment 10 a can be present betweensegments 10 and 11 or 12, from which the segment 10 has been tapered bymeans of drawing. The flexurally rigid part 11, 12 is a metal tubehaving a cylindrical cross section and bent in segments, for example,the flexurally elastic part 10 or more flexurally rigid part 10 a beingguided in the interior thereof. The flexurally elastic part 10 or themore flexurally rigid part 10 a is preferably adhered to the point ofexit 11 a from the metal tube.

The least diameter should not be less than 5 μm. The diameter in theflexurally rigid region (segment 10 a) should not be less than 30 μm.

The fiber receptacle 14 comprises a light source 15 feeding light intothe probe extension 13 and illuminating the target mark 7. The fiberreceptacle 14 is further connected to a displaceable part or element 17of the adjusting means 18 by means of a magnetic changeout interface 16.To this end, the changeout interface 16 also comprises electricalcontacts for supplying power to the light source 15 in addition tomechanical contacts. The entire unit comprising the light source 15,fiber receptacle 14, and probe extension 13 can be changed outautomatically according to the invention.

The adjusting means 18 provides means for adjusting. Using motorizeddrives, translational adjusting of the probe extension 13 is possiblealong the arrows 19 through 22. The arrow 20 indicates that theadjusting occurs in the direction perpendicular to the plane of thedrawing. By adjusting differently in the directions of the arrows 21 and22, a rotation in the direction of the arrow 23 is further implemented.The adjusting means 18 is connected to a holder 25 by means of amagnetic changeout interface 24, thereby producing the indirectconnection to the image processing sensor 2. For example, darkfieldincident light sources, not shown, are mounted in the holder 25 andserve for illuminating the workpiece. According to the invention, theentire unit of the adjusting means 18, fiber receptacle 14, and probeextension 13 can be changed out automatically by means of the changeoutinterface 24. It is particularly provided that the changeout interface24 allows mounting the adjusting means 18 in four positions each rotatedor offset 90° about the optical axis 26. The corresponding mechanicaland electrical connecting elements are thereby present offset from eachother in increments of 90°. Only the connecting elements offset by 180°are shown as examples in the section view of FIG. 1.

FIG. 2 fundamentally shows the device from FIG. 1, but having analternative design for the probe extension 13. Said design comprises amodified bend in the region of the flexurally rigid part or segment 11,so that the probe extension 13 runs at a slight angle to the opticalaxis 26 in the region of the segments 10 and 9. Measurements can therebybe taken on the workpiece 27 at greater depth, without shadowing thebeam path 6 or shaft contact (contact of the flexurally elastic part orsegment 10 or the part or segment 9 with the workpiece 27). Thisconstruction is sensible, particularly for measuring roughness, becauseparticularly small contact shape elements 9 must be used for measuring,whereby the probe extension must be particularly thin and thusflexurally elastic in the region of the segments 9 and 10. In theexample shown in FIG. 2, measurement of the surface of the workpiece 27oriented toward the right in the plane of the drawing is intended.Surfaces oriented in other directions are measured according to theinvention in that the direction of tile of the probe extension ismodified correspondingly. This is preferably done in that the adjustingmeans 18 and thus also the probe extension 13 is rotated correspondinglywhen attaching to the changeout interface 24. Alternatively, a unitcomprising the fiber receptacle 14 and probe extension 13 can be changedin at the changeout interface 16, comprising a region or segment 11 bentin the corresponding direction.

FIG. 3 shows a third embodiment of the arrangement according to theinvention, wherein the vertical deflection of the contact shape element8 is additionally determined by means of the vertically measuringoptical distance sensor 28 by determining the displacement of areflector 34 mounted on the probe extension and serving as a furthertarget mark. This is thus the 3D sensor type.

The distance sensor 28 comprises at least a light source 29, the lightthereof being introduced into the beam path of the image processingsensor 2 approximately along the optical axis 26 past a Foucault gate 30via deflecting mirrors 32 and 33. The light reflected at the reflector34 is guided to a detection unit 31 by the deflecting mirror 33. Thedetection unit 31 is not implemented as a differential diode, contraryto the prior art, but rather as a position-sensitive sensor (PSD) orcamera, whereby the measurable range of the displacement of thereflector 34 along the optical axis 26 and the tilting thereof about thesame are increased. The reflector 34 is further provided for introducingpart of the impinging light into the probe extension 13 in order toilluminate the target mark 7. Said light can originate from the lightsource 29 and the reflector 34 is partially reflective in design, orsaid light originates from a different light source, not shown, ofdeviating wavelength and the reflector 34 is color-sensitive whenreflecting.

The fiber receptacle 14 comprises a flexurally elastic element 35 and arigid retaining element 36. The flexurally elastic element 35 is aplurality of thin leaf spring elements distributed about the opticalaxis 26. Said elements are defocused in the beam path 26, that is,outside of the focal plane present in the region of the target mark 7,and comprise a chucking point 37 in the center to which the probeextension 13 is attached. In the example shown, the probe extension 13is chucked at a right angle in leaf springs running perpendicular to theoptical axis 26 as the flexurally elastic elements 35. Alternatively,the attachment can also be slightly tilted relative to the optical axis26, in order to achieve the advantages explained with respect to FIG. 2.Attaching at positions rotated or offset by 90°, for example, ispossible in turn by means of the changeout interface 24. This ispossible even if the adjusting means 18 is eliminated in the course ofan alternative embodiment of the device according to FIG. 3 and thefiber receptacle 14, particularly the retaining element 36, is attacheddirectly to the changeout interface 24.

FIGS. 4a and 4b show principle views of alternative probe extensions 13according to the invention. For example, in FIG. 4a the regions orsegments 9 of the probe extension 13 run from the target mark 7 instar-shaped directions to one contact shape element 8 each. Not shownare contact shape elements 8 and corresponding regions or segment 9perpendicular to the drawing plane. The branching to the plurality ofcontact shape elements alternatively occurs below the target mark 7.FIG. 4b shows an alternative having a laterally protruding region 9 andcontact shape element 8 attached thereto, wherein the angle to theoptical axis 26 is not 90° but rather an angle of approximately 45° ispresent. Alternatively, all angles can be implemented between 0°(straight embodiment) and approximately 150°.

According to a proposal of the invention, the probe extension 13 or thehollow cylinder receiving the same is geometrically designed as arotational lock with respect to a segment 60 running in the receptacle14 and thus also designated as a mounting segment. This is made possiblein that the peripheral geometry of the mounting segment 60 deviates froma circular geometry and the receptacle or fiber receptacle 14 iscorrespondingly geometrically adapted, so that the mounting segment 14of the probe extension 13 can be received by the receptacle 14 and fixedtherein.

The mounting segment 60 comprises both a solution wherein the probeextension 13 is not enclosed by the hollow cylinder (11, 12) shown inthe drawing views in FIGS. 5a and 5b , that is, the end segment of theprobe extension 13 forming the mounting segment 60 is directly mountedin the receptacle 14 without the hollow cylinder, as well as a solutionin which the probe extension 13 is received by the hollow cylinder andsaid cylinder is mounted in the receptacle 14.

If the probe extension 13 is enclosed by the hollow cylinder or if theprobe extension 13 emerges from the same, then the segment of the hollowcylinder running within the receptacle 14 is designed the same as themounting segment 60.

If the probe extension 13 preferably extends within the hollow cylinderto the mounting segment 60 acting as a rotational lock, then this is nota mandatory feature. Rather, the probe extension 13 can run exclusivelyin the segment 11 running vertically in the drawing, for example, or canend in the horizontal segment 12 prior to the mounting segment 60.

FIGS. 5a and 5b shows principle views of the probe extension 13according to the invention for providing a flat area 80 on the same. Theflat area 80 is, as shown in FIG. 5a , implemented on the hollowcylinder 12 enclosing the probe extension 13 in the region of thechucking point, that is, in the region of the fiber receptacle 14. Thefiber receptacle 14 comprises a contact surface 81, also flat, withwhich the flat area 80 of the probe extension 13 makes contact.

FIG. 5b shows a side view of FIG. 5a in a magnified view, wherein thefiber receptacle 14 and light source 15 are not shown and the region ofthe probe extension 13 facing toward the workpiece 27 and comprising thecontact shape element 8 and optionally the target mark 7 is shown onlypartially, that is, up to the beginning of the drawn region 10. Thefiber of the probe extension 13 running in the interior of the hollowcylinder 12 is shown in the above part. The normal direction 83 of theflat area 80 runs parallel to the optical axis 26 or to the region ofthe probe extension 13 comprising the contact shape element 8 andoptionally the target mark 7, and is therefore pointed downward in thefigure. Alternatively, the flat area can also be implemented at anyother point on the periphery of the hollow cylinder. The fiber of theprobe extension 13 exits the hollow cylinder 11, 12 at the exit point 11a and is fixed thereto by the adhesion. Alternatively, the hollowcylinder can be eliminated and the fiber of the probe extension 13itself is flattened in regions. The coupling efficiency of the lightsource 15, however, is limited by said embodiment.

According to the prior art cited above, the entire arrangement of FIGS.1 through 3 is preferably integrated as a sensor in a coordinatemeasuring machine. For example, reference is made to this end to FIG. 1of DE 10 2004 022 314 or FIG. 12 of DE 10 2010 060 833.

FIG. 6 shows a principle view of a device according to an independentinvention in a first embodiment having a first laterally measuringoptical sensor implemented as an image processing sensor 101 andcomprising a CCD or CMOS camera 102 associated with an optic 103, suchas an optic having fixed magnification and working distance or a zoomoptic having a fixed or adjustable working distance, comprising aplurality of optionally displaceable lenses. The optical sensor 101captures the position and thus the deflection of a target mark 104emerging from a probe extension 105 in the lateral direction or in thetwo lateral directions perpendicular to the optical axis 106 of theoptical sensor 101. A contact shape element 107 is present on theobject-side end of the probe extension 105 and is spherical in designand is brought into contact with the measured object or workpiece 116for measuring and is thereby deflected. In order for the deflection ofthe contact shape element 107 to be able to be captured as fully aspossible by the optical sensor 101, the deflection of the contact shapeelement 107 must be transferred as fully as possible to the target mark104. To this end, a first region 105 a of the probe extension 105 isimplemented having as high a rigidity as possible. Said region connectsthe contact shape element 107 to the target mark 104, wherein thecontact shape element 107 and the target mark 104 can optionally beintegrally designed with the first region 105 a. In order that very lowcontact forces are achieved for protecting the workpiece 116 againstdamage, a second region 105 b of the probe extension 105 is implementedhaving a significantly lower rigidity than the region 105 a. The secondregion 105 b emerges from the target mark 104 and runs facing away fromthe contact shape element 107. A preferred solution for implementing thesame is to select the elastic modulus E of the region 105 a to besignificantly greater than the elastic modulus of the region 105 b. Thiscan be done, for example, by hardening the region 105 a or byappropriate material selection. Potential materials according to theinvention for the region 105 a include hard materials such as steel,diamond, graphene, or tungsten, for example, and for the region 105 b,soft materials such as glass, glass fiber, plastic, or plastic fibersuch as polyethylene, polypropylene, polyvinylchloride, or polyethyleneterephthalate. In order to connect the first or second region 105 a and105 b to the target mark 104 or the contact shape element 107, adhesion,welding, or splicing is provided according to the invention.Alternatively, the region 105 b having the target mark 104 and theregion 105 a having the contact shape element 107 can form a unit, forexample produced by splicing or generally by forming, for example in aheated state. In a further alternative, the region 105 a can also form aunit with the contact shape element 107 and the target mark 104.

According to an alternative solution for the object of the invention,the dimensions of the region 105 a, particularly the length andthickness, or diameter, are implemented so as to have a greaterrigidity. This is possible only within certain limits, however, as agreater diameter means that the contact shape element 107 must beimplemented having a greater diameter as well, and particularly holes ofsmall diameter can thereby no longer be measured. Reducing the length ofthe region 105 a has the result that measurements can no longer be takenat great depths in a hole.

The side of the probe extension 105 further from the object emerges froma mounting element 108, for example means for adjusting the location ofthe probe extension 105 or a changeout interface for placing the probeextension, as can be found in the prior art described above, andconnected to the optical sensor 101. The arrangement according to theinvention is thereby a sensor integrated in a coordinate measuringmachine 130, as is labeled in FIG. 8 as reference numerals 132 and 128,for example.

FIG. 7a shows a principle view of a device according to the invention ina second embodiment. In addition to the image processing sensor 101, adistance sensor 109 is integrated, the measurement beam 112 thereofbeing coupled into the beam path of the image processing sensor 101 inthe direction of the optical axis 106 by means of a semi-transparentdeflecting mirror 110 and reflected by a second target mark 111 mirroredon the side thereof facing toward the sensor. The target mark 111 can,as previously explained with respect to the first target mark 104, beconnected to the first region 105 a by means of adhesion, welding, orsplicing, or can form a unit with the same and optionally also the firsttarget mark 104 and optionally also the first region 105 a presentbetween the first target mark 104 and the contact shape element 107, andoptionally also with the contact shape element 107.

In order that the deflection of the contact shape element 107 istransferred as fully as possible to the first target mark 104 and to thesecond target mark 111, the first region 105 a of the probe extension105 extends between the contact shape element 107, the first target mark104, and the second target mark 111. The second region 105 b of theprobe extension 105 is formed by one or more flexible connectingelements, as can be seen in DE102010060833 in FIGS. 8-10, for example.The second region 105 b thereby emerges from the mounting element 108and ends at the first region 105 a at a point between the first targetmark 104 and the second target mark 111. Alternatively, the secondregion 105 b ends directly at the second target mark 111, as shown inexcerpts in FIG. 7b and self-explanatory to this extent. It is furtherprovided according to the invention that the first target mark 104simultaneously takes on the function of the second target mark 111 inthat the first target mark 104 is mirrored on the side thereof facingthe sensor, as shown in excerpts in FIG. 7 c.

It is thus also possible by means of the invention to implement verylong probe pins or probe extensions of a plurality of millimeters inlength, for example greater than 5 mm, up to a few centimeters inlength, for example 3-15 cm.

The first region 105 a should have a length greater than 5 mm,preferably up to 10 cm. The diameter of the first region 105 a should bebetween 10 μm and 500 μm.

With respect to the second region 105 b, preferred values for the lengthare 10 mm to 100 mm, and/or for the diameter are 10 μm to 1 mm. Whenselecting the dimensions, however, it must be considered according tothe previous embodiment that the first region 105 a has a greaterrigidity than the second region 105 b according to the teachingaccording to the invention and the specifications in this context.

Additional potential special designs are shown in FIGS. 7d and 7e . FIG.7d shows a probe extension 105 in an L shape, that is, having aprotruding region 105 a′, at which the contact shape element 107 ispresent. FIG. 7e shows a probe extension 105 in the form of a starprobe. One contact shape element 107 for contacting the workpiece ispresent at each of the plurality of regions 105 a′. The regions 105 a′can thereby also comprise greater lengths of a plurality of millimetersup to a few centimeters. The regions 105 a′ shown in FIGS. 7d and 7ehave the greater rigidity corresponding to the region 105 a to this end.

The sufficiently known principle, shown again in FIG. 8, of a coordinatemeasuring machine 130 comprises a base frame 113 made of granite, forexample, and having a measurement bench 114 on which an object orworkpiece 116 to be measured is positioned in order to measure thesurface properties thereof, that is, features or structures thereof.

A portal 119 is adjustable in the Y direction along the base frame 112.To this end, columns or stands 120, 122 are slidingly supported on thebase frame 112. A traverse 124 emerges from the columns 120, 122, alongwhich a carriage is displaceable, said carriage in turn receiving a ramor column 126 adjustable in the Z direction. A sensor or measurementsystem 132 emerges from the ram 126 or optionally from a changeoutinterface 128 connected to the ram and can be implemented as a tactilesensor and, if the ram 126 comprises an image processing sensor,measures in a tactile/optical manner Reference is made, however, tosufficiently known techniques, as well as with respect to furthersensors used such as laser distance sensors, white lightinterferometers, image processing sensors, X-ray sensors, or chromaticfocal sensors or a confocal scanning measurement head, without therebylimiting the teaching according to the invention. With respect to thetactile/optical measurement, reference is made in particular to thedisclosure in EP-B-988 505 (WO98/57121), the contents of which arereferenced.

The sensor or sensors are selected and used according to the measurementtask, in order to optimally configure the coordinate measuring machine130, then also referred to as a multisensor coordinate measuringmachine, for the particular measurement task. Problems occurring intypical coordinate measuring machines are solved at the same time.

In order to be able to use the coordinate measuring machine 130 havingthe suitable sensor, the coordinate measuring machine can comprise asensor changeout unit. A plurality of sensors can thus be selectivelyloaded to the coordinate measuring machine 130 by means of a changeoutinterface and can be changed out by hand or by automatically retrievingfrom a parking station.

FIG. 9 shows a first embodiment of an independent arrangement accordingto the invention for determining geometric features and structures, forexample here the diameter of a hole 218, on a the workpiece 201. Thedetermining is done by means of the tactile/optical sensor according tothe invention, comprising at least the flexurally elastic probeextension 203, from which a contact shape element 204 emerges on oneside and a first target mark 202 emerges on the other side, saidextension being attached to a mounting element 209, wherein by couplingto the light source 210 light, such as from an LED or a laser lightsource, is introduced into the probe extension 203, and by means of thelaterally measuring optical sensor 206, comprising at least one imaginglens 207 and one receiver 208 such as a CCD or CMOS sensor, in that whenthe contact shape element 204 contacts the workpiece 201, the resultinglateral deflection of the target mark 202 associated with the contactshape element 204 is captured by the beam path 216 of the laterallymeasuring optical sensor 206 and is imaged on the receiver 208 by meansof the imaging lens 207. The laterally measuring optical sensor 206 isimplemented as an image processing sensor and determines the magnitudeand direction of the deflection of the target mark 202, particularly bydetermining the deflection of the light spot 215. The light spot 215 isformed by the light 219 from the light source 210 reflected within theprobe extension 203. The reflections thereby occur at the layer orcoating 213 of the contact shape element 204 and the layer or coating212 of the target mark 202. The target mark 202, however, isparticularly preferably coated only on the side thereof facing towardthe laterally measuring optical sensor 206, particularly to the equatorof the spherical target mark 202, so that the light spot 215 is visibleto the laterally measuring optical sensor 206, that is, can be imaged onthe detector 208 by the lens 207. The light from the light source 210 isfurther reflected once or a plurality of times at the coating 214 of theregion 205 of the shaft of the probe extension 203 running between thetarget mark 202 and the contact shape element 204, and thus retainedwithin the shaft, shown by the arrow 220. In order to avoid light lossesin the region between the mounting element 209 and the target mark 202as well, of course said region of the probe extension 203, that is, theregion 211, can also have a reflective or fluorescing layer.

The layer 213 of the contact shape element 204, in particular, can alsobe covered by means of a hard-surface or wear-resistant protective layersuch as a silicon nitride layer applied to the outside of the contactshape element 204 over the reflecting or fluorescing layer 213.

FIG. 10 shows an arrangement according to the invention wherein a secondsensor 221 is additionally used for indirectly determining thedeflection of the contact shape element 204. In order to provide asensor system for measuring in three dimensions, the second sensor isimplemented as a distance sensor and determines the deflection of thecontact shape element 204 by determining the change in position of thesecond target mark 226 in the direction of the measurement beam 225 ofthe distance sensor 221, in the direction perpendicular to thedeflection of the contact shape element 204 determined by the laterallymeasuring optical sensor 206.

To this end, the distance sensor 221 comprises the light source 210 a,preferably generating a light beam directed toward the second targetmark 226 by means of the partially transparent deflecting mirrors 223 band 223 a and the lens 207 and reflected by the same. The distancesensor is preferably implemented as a Foucault sensor in which a gate229 is used. The measurement beam 225 reflected by the second targetmark 226 is deflected onto the differential diodes 224 for analysisafter reflecting at the partially transparent deflecting mirror 223 a.

The probe extension 203 is preferably attached to a mounting element 217in the region between the first target mark 202 and the second targetmark 226 by means of one or more flexible retaining elements 221, inorder to allow the probe extension to deflect in the measurementdirection of the distance sensor. The mounting element 217 is preferablyconnected to a coordinate measuring machine, preferably to the samecomponent as the first and second sensors 206, 221. With respect tofurther embodiments for the probe extension 203, first and second targetmarks 202, 226, retaining elements 221, and the region in which theretaining elements 221 are connected to the probe extension 203,reference is made to the disclosed contents of DE 10 2010 060 833.

According to the prior art cited above, the entire arrangement of FIGS.9 and 10 is preferably integrated as a sensor in a coordinate measuringmachine. For example, reference is made to this end to FIG. 9 of DE 102004 022 314 or FIG. 12 of DE 10 2010 060 833.

FIG. 11 shows the sequence of the steps in principle according to theinvention of the independent invention for automatically measuringgeometric features or contours in a preferred embodiment. Prior toactually measuring the workpiece, the specified data 301 of all eligibleworkpieces (“Workpiece 1”, “Workpiece 2”, through “Workpiece n”) arerecorded and saved. The specified data thereby comprise “specifiedgeometries” taken from the technical drawings and saved in a CAD file(“CAD”), for example. The “tolerances” associated with the features arefurther saved in said file or a separate file. The association offeatures and tolerances can also be present in the form of an inspectionplan. The specified data further comprise the template images ortemplates (“Template 1”, “Template 2”, through “Template i”) of theeligible workpieces 1, 2, through n, each recorded under different lightsettings.

For the actual measuring of the workpiece, an image 302 or an overallimage merged from a plurality of individual images (“Image 1”, “Image2”, through “Image m”) is recorded by means of an optical sensor,preferably an image processing sensor comprising at least an optic and acamera. Said image is referred to below as the image.

The image 302 is compared with all template images (“Template 1”,“Template 2”, through “Template i”) of the specified data 101 by meansof the step “Correlation analysis”. The specified data associated withthe template having the greatest match, particularly the CAD data(“CAD”) and “tolerances” are processed further, together with thedetermined “location” of the workpiece with respect to the specifieddata, as “selected specified data”, particularly “specified geometries”,in the next step. A rough fit of the image 1 with respect to the“specified geometries”, not shown, is performed using the “location” ofthe “selected specified data.” Then the measurement window for the stepof “feature extraction” of the features or contours from the image isdefined. In addition, the “selected specified data” are used in the“fitting” step for fitting the extracted features to the specified data,particularly to the “specified geometries.”

The fitting can thereby be performed with respect to the specifiedgeometries in the form of a “BestFit” fitting or additionallyconsidering the tolerances in the form of a so-called “ToleranceFit”fitting.

The last step presents the “results output”, wherein the “dimensions”determined for features and optionally the “deviations” from thespecified values are indicated and preferably additionally the“compliance with tolerances” and the dimensions of “minimum underrun” or“maximum overrun” of the tolerances or specified values are output.

FIG. 12 shows an arrangement of the multisensor system having a tactilesensor head 401 changed in, explaining an independent invention. Anoptical sensor 402 comprising at least a camera 403 and an optic 404(having an optical axis 404 a) and a first changeout interface 405 arefixedly disposed on a coordinate measuring machine, for example.Brightfield lighting 406 and a beam path of a laser distance sensor 407,for example using the Foucault principle, are further reflected into thebeam path (optical axis 404 a) of the optical sensor 402, and darkfieldlighting 408 disposed externally around the optic 404 and the firstchangeout interface 405 are also shown.

An adapter 410 is interchangeably disposed at the first changeoutinterface 405 and comprises a base element 409 of a tactile probe systemor tactile sensor. The base element 409 comprises a second changeoutinterface 411 on which the measurement system 412 of the tactile sensorhead 401 is interchangeably attached, and is in turn connected to aprobe insert 413, preferably interchangeably connected, said insert inturn comprising a plate 414, a probe pin 415, and a probe element 416. Aworkpiece 417 is contacted at a measurement location 418 by means of theprobe element 416 and measured in that the deflection is determined bythe measuring system 412. Adapters 410 having a tactile sensor head 401can be placed in a first parking station, not shown. The measurementsystem 412 can be placed in a second parking station, not shown. Theprobe insert 413 can be changed out manually or placed in a furtherparking station automatically.

FIG. 13 shows the tactile sensor, that is, the adapter 40 having thebase element 409 and the tactile sensor head 401 attached thereto,placed in the first parking station, not shown. A tactile/optical sensor419 is now attached at the first changeout interface 405. The deflectionof a probe element 420 mounted on a flexurally elastic probe extension420 a is captured directly by the optical sensor 402, preferablyimplemented as an image processing sensor, and indirectly by thedistance sensor 407 by means of a reflector 420 b mounted on theflexurally elastic probe extension 420 a The probe element 420 contactsthe workpiece at the measurement point 418.

FIG. 14 shows an auxiliary lens 421 changed in at the first changeoutinterface 405 in place of the tactile/optical sensor 419, said lensbeing used for optimally directly measuring the workpiece 417 by meansof the distance sensor 407 at the measurement location 418. If theauxiliary lens 421 is placed in the first parking station, then thedirect measuring of the workpiece 417 by the optical sensor 403 isimplemented, wherein the center of the measurement range captured by thecamera 403 defines the measurement location 418. In this case, theauxiliary lens 421 can be understood as the sensor head of the distancesensor 407.

FIG. 15 shows a first embodiment of an independent arrangement accordingto the invention for determining geometric features and structures of aworkpiece 610. Measurements on the workpiece 610 are thereby performedby contacting by means of a contact shape element 601 being deflectedwhen contacting the workpiece 610 and emerging from a flexurally elasticprobe extension 604. The deflection is determined by two sensors, alaterally measuring optical sensor 603, preferably an image processingsensor, determining the deflection perpendicular to the optical axis 602thereof, as is sufficiently described in the prior art, and a verticallymeasuring interferometric distance sensor 605 determining the deflectionin the direction of the optical axis 602. Together with the flexurallyelastic probe extension 604 and additional parts of a preferablyinterchangeable unit 606 described below, said two sensors form thetactile/optical sensor according to the invention.

The tactile/optical sensor preferably comprises an imaging optic 607made primarily of a plurality of lenses and also potentially implementedas a zoom optic, in order to form a beam path 608 along the optical axis602, and focused on the contact shape element 601 or a target mark 609associated therewith. The optical axis 602, the imaging optic 607, andthe beam path 608 are first associated with the laterally measuringoptical sensor 603, but are then also used for the interferometricdistance sensor 605.

As previously found thoroughly in the prior art, the shadowing of thecontact shape element 601 or the target mark 609 under transmitted lightillumination or the self-illuminated contact shape element 601 or theself-illuminated target mark 609 can be captured. In the context of thepresent specification, the second variant, know as self-illumination, ispreferably used. Said self-illumination is generated in that light onthe side 626 of the probe extension 604 facing away from the workpiece,that is, on the side of the probe extension further away from or facingaway from the contact element, is coupled into the same and transmittedtherein to the contact shape element 601 or, if present, to the targetmark 609. To this end, the probe extension 604 is implemented for atleast partially transmitting light, for example as a glass or plasticfiber. The contact shape element 601 and target mark 609 are implementedby a coating according to the prior art, so as to emit the infed light,said light being captured by the imaging optics 607 and imaged in thedirection of the analysis units 612, 613 of the sensors 603 and 605. Tothis end, the beam paths of both sensors run jointly to an opticalsplitter 611 and are guided thereby on one side in the direction of theanalysis unit 612 of the laterally measuring sensor 3 and on the otherside in the direction of the analysis unit 613 of the interferometricsensor 605. The optical splitter 611 is implemented as a semitransparentfilm (pellicle) or as a splitter cube, for example. The analysis units612, 613 are cameras having preferably planar receiver surfaces, such asCCD or CMOS cameras, for example, and optionally have additional imaginglenses connected upstream thereof.

The vertically measuring interferometric distance sensor 605 comprises,in addition to the imaging optic 607 and the analysis unit 613, thelight sources 614 and 615, the optical fibers 617 a, 617 b, and 617 c,and a coupling arrangement 616. The latter typically comprises a fiberend having a beam-shaping optic connected upstream and couples the beam618 from the light sources 614 and 615 out of the optical fiber 617 c,so that coupling into the probe extension 604 is made possible. Thelight from the two light sources 614 and 615 is combined by a Y-couplerconnecting the optical fibers 617 a and 617 b to the optical fiber 617c. The light sources 614 and 615, the optical fibers 617 a, 617 b, and617 c, and the coupling arrangement 616 can alternatively be disposeddirectly in the unit 606.

The preferably interchangeable or changeable unit 606 further comprisesthe probe extension 604, means 637 for attaching the probe extension,means 622, 625 for splitting the beam 618 into the measurement beam 619and the reference beam 620, means 622, 623, 624 for deflecting themeasurement beam 619 in the direction of the side 626 of the probeextension 604 facing away from the workpiece 610, and means 627, 628,629, 630, 631, 632, 633, 634 such as reflectors for forming a referencebeam path 621 a, 621 b, 621 c. To this extent express reference is madeto the self-explanatory figures. The unit 606 further comprises means,not shown, such as permanent magnets, for releasably mounting on achangeout interface 635. The coupling of the beam 618 preferably takesplace laterally to the unit 606 at an interface 636 implemented as anopening, for example, but can also take place within the changeoutinterface 635. An additional deflection of the beam 618 may then benecessary. If the light sources 614 and 615, the optical fibers 617 a,617 b, and 617 c, and the coupling arrangement 16 are disposed directlyin the unit 6, then the required electrical feeds to the light sources614 and 615 are guided by means of the changeout interface 635.

In the first arrangement according to the invention shown in FIG. 15,the contact shape element 601 emerges from the probe extension 604; thebeam 618 is split into the measurement beam 619 and the reference beam620 at the optical splitting layer 622, wherein the optical splittinglayer 622 simultaneously deflects the measurement beam 619 in thedirection of the side 626 of the probe extension 604 facing away fromthe workpiece, whereby the measurement beam 619 is coupled into theprobe extension 604; and the reference beam 620 is deflected by thereflectors 627 and 628 to the reference mirror 629, reflected by thesame, and again deflected onto the optical splitting layer 622 andimaged by the same in the direction of the imaging optic 607 and thus inthe direction of the analysis unit 613. The reference beam path therebyruns partially at an angle, particularly a right angle, to the opticalaxis (segments 621 a) and partially parallel to the optical axis(segment 621 b), and thus is folded (deflected) a plurality of times.The reflectors 627, 628, and 629 are thereby present outside of the beampath 608, particularly laterally adjacent to the optical beam path 608.

In the arrangements according to the invention shown in segments in FIG.16, in which solely the unit 606 modified in comparison with FIG. 17 isshown, the contact shape element 601 and the target mark 609 emerge fromthe probe extension 604; the beam 618 is split into the measurement beam619 and the reference beam 620 at the optical splitting layer 625, themeasurement beam 619 is deflected in the direction of the side 626 ofthe probe extension 604 facing away from the workpiece by the surface ofa deflecting device 624 implemented as a reflector 623 such as amirrored prism, whereby the measurement beam 619 is coupled into theprobe extension 604; and the reference beam 620 is imaged in thedirection of the imaging optic 607 and thus in the direction of theanalysis unit 613 by the reflectors 630, 631, 632, 633, and 634. Thelast reflector 634 passed through, as shown, is preferably formed by afurther mirrored surface of the deflecting device 624. The referencebeam path thereby runs partially at a right angle to the optical axis(segment 621 a), partially at an angle to the optical axis (segment 621c) and partially parallel to the optical axis (segment 621 b), and thusis folded (deflected) a plurality of times. The reflectors 630, 631,632, and 633 and the optical splitter layer 625 are thereby presentoutside of the beam path 608, particularly laterally adjacent to theoptical beam path 608.

Also partially shown in FIG. 16 as an example is the optionally usableadditional distance sensor. The beam path 638 of the further distancesensor, for example, is reflected into the beam path 608 by a furtheroptical splitter, comparable to the optical splitter 611. Correspondinglenses disposed upstream, however, cause the imaging optic 607 to focusthe beam path 638 not on the contact shape element 601 or the targetmark 609, but rather on the additional target mark implemented as areflector on the end 626 of the probe extension 604 facing away from theworkpiece. Said reflector 626 is preferably only partially mirrored, inorder to transmit the measurement beam 619 at least partially and tooptionally allow self-illumination of the contact shape element 601 orthe target mark 609 by the light of the beam path 638, whereby thefunction of the additional distance sensor is possible regardless of theswitched state of the interferometric distance sensor 605. Saidoperating mode is described in DE 10 2010 060 833, for example.

By modifying the arrangement of the positions, particularly the spacingof the reflectors in the reference beam paths according to FIG. 15 or16, the optical path distance of the reference beam path can be adaptedto the optical path length of the measurement beam path travelled by themeasurement beam 619. Probe extensions 604 having different lengths canthereby be implemented.

According to the prior art cited above, the entire arrangement of FIGS.15 and 16 is preferably integrated as a sensor in a coordinate measuringmachine. For example, reference is made to this end to FIG. 1 of DE 102004 022 314 or FIG. 12 of DE 10 2010 060 833.

FIG. 17 shows a measurement bench 701 and structures 702 mounted thereoncorresponding to the independent gage or device according to theinvention. The structures 702 are lines spaced apart at irregularintervals and mounted on the entire edge region of the measurement bench701 and not completely covered by the workpiece 703 in any of theadjacent overlapping individual images 704 through 704 f. The individualimages 704 a through 704 f are recorded one after the other by means ofan image processing sensor, not shown, and then merged into an overallimage 705 comprising the complete workpiece 703. The exact positiontaken by the image processing sensor during the recording of theindividual images 704 a through 704 f relative to the workpiece 703 doesnot need to be known according to the invention, because the structures702 are captured at least partially in all individual images 704 athrough 704 f and the location of each individual image 704 a through704 f can be derived therefrom. Manual or motorized axis drives are usedfor displacing the sensor and/or the workpiece relative to each other,wherein preferably no measuring axes are present. Alternatively, thesegment of the workpiece imaged in the individual images can also bevaried by deflecting the beam path of the optical sensor internally inthe sensor or externally, for example by deflecting and/or refractingthe measurement beam of the sensor, or by tilting the sensor.

The invention claimed is:
 1. A method for determining geometric featuresand structures on a workpiece by means of a tactile/optical sensorintegrated in a coordinate measuring machine, the tactile/optical sensorcomprising at least a laterally measuring optical image processingsensor, and an at least partially flexurally elastic probe extension, atleast the following emerging from the probe extension: a contact shapeelement deflecting when contacting the workpiece, the lateral deflectionof the contact shape element perpendicular to the optical axis of thelaterally measuring optical sensor being captured by means of the same,wherein the probe extension emerges from a fiber receptacle to which aflexurally elastic part is connected, to which the contact shape elementis connected, wherein a probe extension is changed in, such thatmeasurement points on the workpiece can each be determined in asingle-point mode, wherein the following steps are carried out: thecontact shape element and workpiece are displaced toward each otherrelative to each other until a predefined deflection of the contactshape element has been achieved, the contact shape element and workpieceare displaced away from each other relative to each other at least untilthe contact shape element is no longer deflected, the deflection of thecontact shape element is determined according to at least one procedurestep of the group deflection during the displacement of the contactshape element and the workpiece toward each other, during thedisplacement of the contact shape element and the workpiece away fromeach other, between these two displacements, one measurement point eachis calculated from the one or more determined deflections and thelocation of the tactile/optical sensor relative to the workpiece in eachcase using the positions of the measurement axes of the coordinatemeasuring machine, or wherein a probe extension is changed in by meansof which a plurality of measurement points, offset from each other onthe workpiece can each be determined in scanning mode, wherein thefollowing steps are carried out: the contact shape element and workpieceare displaced toward each other relative to each other until apredefined deflection of the contact shape element has been achieved thecontact shape element and workpiece are displaced relative to each otheralong a path, wherein the contact shape element and the workpiece remainin contact, and wherein the deflection of the contact shape element isdetermined cyclically during the displacement the contact shape elementand workpiece are displaced relative to each other away from each otherat least until the contact shape element is no longer deflected theplurality of measurement points are calculated from the plurality ofdetermined deflections and the location of the tactile/optical sensorrelative to the workpiece in each case using the positions of themeasurement axes of the coordinate measuring machine.
 2. The methodaccording to claim 1, wherein the tactile/optical sensor comprisesadditionally a vertically measuring optical distance sensor.
 3. Themethod according to claim 1, wherein at least one target mark associatedwith the contact shape element emanates from the probe extension, saidtarget mark is deflected when the contact shape element contacts theworkpiece.
 4. The method according to claim 3, wherein the verticaldeflection of the contact shape element or of the target mark along theoptical axis of the laterally measuring optical sensor being captured bymeans of the distance sensor.
 5. The method according to claim 1,wherein a target path such as a spline is defined for the path and isformed by one or more prescribed curves in space, wherein the curves aredefined based on previously measured points, or a model of theworkpiece, or from basic geometric shapes, and the path eithercorresponds to the target path (uncontrolled scanning), or follows thetarget path providing for the deflection of the contact shape element orthe target mark, in at least two coordinate directions defined by ascanning plane (controlled scanning).
 6. The method according to claim1, wherein the path is defined by a starting point and an ending point,and by a starting direction or a scanning plane, and wherein, betweenthe defined points, the path is determined by providing for thedeflection of the contact shape element or target mark by the locationof the workpiece surface being contacted.
 7. The method according toclaim 1, wherein the deflection during the displacement on the path iscontrolled between a minimum and a maximum value about a targetdeflection by displacing corresponding coordinate measuring machineaxes.
 8. The method according to claim 7, wherein the control takesplace perpendicular to a scanning plane, or in the two spatialdirections within the scanning plane, or in all three spatialdirections.
 9. The method according to claim 1, wherein when controllingin the two spatial directions within the scanning plane, the controltakes place in the direction of the deflection, and the displacementalong the path within the scanning plane takes place perpendicular tothe deflection projected into the scanning plane, wherein the sense ofdirection of the displacement is defined so as to form the smaller angleto the previous direction of displacement.
 10. The method according toclaim 9, wherein the control takes place in the direction of thedeflection projected into the scanning plane.
 11. The method accordingto claim 1, wherein the probe extension transitions from a flexurallyelastic region adjacent to and directly above the contact shape elementor target mark into a region having a greater diameter, wherein thelength of the region running directly above the contact shape element orthe target mark to the region of the greater diameter is selected to beless than 2 mm for use for scanning measurement, or greater than 2.5 mmfor single-point measurement.
 12. The method according to claim 11,wherein the length of the region running directly above the contactshape element, or the target mark, to the region of the greater diameteris from 0.2 mm to 1.5 mm, for use for scanning measurement, or from 3 mmto 6 mm, for single-point measurement.
 13. The method according to claim1, wherein two deflection signals perpendicular to each other, areextracted from each of the images recorded by the laterally measuringoptical sensor and a third deflection signal, perpendicular to the firsttwo deflection signals, is provided by the vertically measuring distancesensor in order to determine the deflection of the contact shape elementin 3D and to determine the measurement points therefrom.
 14. The methodaccording to claim 1, wherein the recording of the image used fordetermining the deflection of the contact shape element in 2D in eachcase and of the associated third deflection signal provided by thedistance sensor are recorded at the same point in time, controlled by atrigger line, as the recording of the positions of the measurement axesof the coordinate measuring machine.
 15. The method according to claim1, wherein the deflection signals are extracted from the images recordedby means of the laterally measuring optical sensor in that the locationof the contact shape element or the target mark in each image isdetermined in comparison with the previously calibrated location in thenon-deflected state, wherein the previously calibrated location and eachparticular location are determined by identifying the contour of thecontact shape element or the target mark in the image by determining thecentroid or center point of the contour, or are determined by means ofcorrelation methods, wherein the maximum correlation to a previouslydetermined template of the image of the contact shape element or thetarget mark is determined, wherein the correlation is analyzed in aplurality of different locations of the template relative to each image.16. The method according to claim 1, wherein a cross-correlation isapplied, wherein the fact that the template and the image are recordedunder different lighting is provided for as an additional parameter,thus the template or image are normalized accordingly prior todetermining the correlation.
 17. The method according to claim 16,wherein the template and the image are recorded under differentbrightness.
 18. The method according to claim 1, wherein the correlationor the correlation coefficient is determined first at reduced resolutionof the image or template, and a rough location of the contact shapeelement or the target mark is determined, and then at increasedresolution in a limited image region around the roughly determinedlocation.
 19. The method according to claim 18, wherein the method isrepeated at stepwise increasing resolution and stepwise limitation ofthe image region.
 20. The method according to claim 1, wherein prior todetermining a correlation, regions of the image excepted from thecorrelation analysis are determined using simple test parameters forfiltering the maximum value candidates.
 21. The method according toclaim 1, wherein the probe extension is adjusted relative to thelaterally measuring optical sensor in one, two, or three translationaland one, two, or three rotational degrees of freedom.
 22. The methodaccording to claim 1, wherein the region of the probe extensioncomprising the contact shape element is adjusted to an angle of 0°<α<15°relative to the optical axis of the laterally measuring optical sensor,in that: a fiber receptacle comprising a probe extension is used, saidprobe extension comprising a corresponding preset bend between theregion comprising the contact shape element and the region of the fiberreceptacle, or a fiber receptacle comprising a fixing locationimplemented accordingly is used, or the means for adjusting are adjustedaccordingly, and that the contact shape element or the target mark aredisposed in the focal region of the laterally measuring optical sensor.23. The method according to claim 1, wherein a probe extensioncomprising a bend or a star-shaped branching to a plurality of contactshape elements between the contact shape element and the target mark isused or changed in for measuring undercuts or other featuresinaccessible to straight probe extensions.
 24. The method according toclaim 1, wherein the imaging scale when deflecting in the verticaldirection is held constant by using a telecentric optic having a fixedmagnification or a telecentric zoom stage of a zoom optic.
 25. Themethod according to claim 1, wherein a zoom optic is used fordetermining the lateral deflection, wherein a zoom stage is selectedcomprising an imaging scale adapted to the diameter of the contact shapeelement or target mark being captured in each case, adapted so that theimage of the contact shape element or target mark, including the maximumpermissible deflection thereof, is completely captured by the zoom opticand the resolution is maximized.
 26. The method according to claim 1,wherein the vertically measuring optical distance sensor is a sensorusing the Foucault principle, wherein a lighting source illuminates onlya limited part of the aperture of the optic used on the object forimaging, or wherein a linear or planar detection unit such as aposition-sensitive diode (PSD) or camera is used for determining thelocation of the lighting reflected by the workpiece, wherein adifferential signal is determined from the sum signals, or the beamcentroid is determined by analyzing the intensities of the individuallight-sensitive elements of at least one partial region of the cameraarea.
 27. The method according to claim 1, wherein the tactile/opticalsensor is integrated in the coordinate measuring machine together withadditional tactile, optical, or computed-tomography sensors.
 28. Themethod according to claim 1, wherein the brightness of the light emittedby the contact shape element or target mark is determined by the cameraof the image processing sensor and is regulated to a constant value bycontrolling the light source for illuminating the contact shape elementor the target mark.
 29. A device for determining geometric features andstructures on a workpiece by means of a tactile/optical sensor at leastmade of an at least partially flexurally elastic probe extension, atleast the following emerging from the probe extension: a contact shapeelement for deflecting when contacting the workpiece, and a target markassociated with the contact shape element for deflecting when thecontact shape element contacts the workpiece such that the lateraldeflection thereof, perpendicular to the optical axis of a laterallymeasuring optical sensor can be captured by means of the optical imageprocessing sensor, wherein the side of the target mark facing away fromthe optical sensor is at least partially coated with a reflecting orfluorescing layer and that the region of the shaft of the probeextension running between the target mark and the contact shape elementor the contact shape element is at least partially coated with areflecting or fluorescing layer.
 30. The device according to claim 29,wherein the region of the shaft of the probe extension running betweenthe target mark and the contact shape element is entirely coated and thecontact shape element is entirely coated with a reflecting orfluorescing layer.
 31. The device according to claim 29, wherein thelayer is a metal layer and is covered by a hard-surfaced orwear-resistance protective layer, at least in the region thereof makingcontact with the object.
 32. The device according to claim 29, whereinthe target mark is spherical or nearly spherical in design and is coatedwith the reflecting or fluorescing layer on the area thereof facing awayfrom the optical sensor up to or approximately up to the equator. 33.The device according to claim 29, wherein the light emitted by thereflecting or fluorescing layer produces an image associated with thetarget mark, wherein the image associated with the target is a lightspot arising due to bundling on the optical sensor, such that thelateral deflection thereof can be captured by the laterally measuringoptical sensor.
 34. The device according to claim 29, wherein a secondtarget mark emerges from the probe extension and can be captured bymeans of a second sensor, wherein the second sensor is a distancesensor.
 35. The device according to claim 29, wherein thetactile/optical sensor is integrated in a coordinate measuring machine,together with additional tactile, optical, or computed-tomographysensors.
 36. A method for determining geometric features and structureson a workpiece by means of a tactile/optical sensor at least made of anat least partially flexurally elastic probe extension, at least thefollowing emerging from the probe extension: a contact shape element fordeflecting when contacting the workpiece, and a target mark associatedwith the contact shape element and deflecting when the contact shapeelement contacts the workpiece such that the lateral deflection thereof,perpendicular to the optical axis of a laterally measuring opticalsensor having the optical sensor is captured, wherein the beam emittedby at least one part of the reflecting or fluorescing layers is imagedon the laterally measuring optical sensor by means of a device accordingto claim 29, and wherein that the lateral deflection of the contactshape element is determined from the image.
 37. The method accordingclaim 36, wherein the second target mark emerging from the probeextension is captured by the second sensor, wherein the second sensor isa distance sensor, and wherein the measurement beam of the distancesensor is at least partially reflected at the second target mark. 38.The method according to claim 36, wherein the tactile/optical sensor isintegrated and used in the coordinate measuring machine together withadditional tactile, optical, or computed-tomography sensors.